Upgrade of the LARES-lab Remote Controllable Thermo-vacuum

Facility

Lab Improvements for Remote Testing and e-Learning

Claudio Paris

1, 2

and Giampiero Sindoni

Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89/a, 00184, Rome, Italy

Scuola di Ingegneria Aerospaziale, Sapienza University of Rome, Via Salaria 851, 00138, Rome, Italy

Keywords:

Thermo-vacuum Testing, Space Simulator, Remote Lab, e-Learning, LARES.

Abstract:

The LARES-lab facility was speciﬁcally designed to perform tests in simulated space environment on the

optical payload of the LAser RElativity Satellite (LARES). Since the facility was intended to perform de-

manding tests, it was equipped with the best technology available at the time. After the launch of LARES the

facility was used both for testing payloads and small university satellites and for didactic activities. Testing

in simulated space environment is fundamental for the development of a space mission, so a well equipped

facility in a university is a precious resource for teaching. At the moment, room dimension and the location

limit the access to the lab to a small number of students per lesson. To fully exploit the didactic potential of

the LARES-lab an improvement over the remote control operation of the thermo-vacuum chamber is planned.

The project, which has been described in a previous paper, is currently under development. A new device

implemented is a robotic arm to manipulate some mechanisms and to gain experience for remote controlling

other servo mechanisms. This way both researchers and students can operate the facility remotely with mini-

mal need of on site operations. Once the improvements will be fully operational, LARES-lab will allow access

to the laboratory didactic activities to a much larger number of students.

1 INTRODUCTION

LARES-lab facility was designed for performing tests

on the optical payload of the LAser RElativity Satel-

lite (LARES) (Paolozzi et al., 2012a; Paolozzi et al.,

2012b). LARES mission was supported and funded

by the Italian Space Agency (ASI) (Paolozzi et al.,

2011), while the European Space Agency (ESA) pro-

vided the launch with the maiden ﬂight of the new

launcher VEGA (Paolozzi and Ciufolini, 2013). The

goal of the mission is the precise measurement of

frame-dragging (Ciufolini et al., 2012b), predicted by

General Relativity, improving the previous 10% accu-

racy obtained with data from LAGEOS and LAGEOS

2 satellites (Ciufolini and Pavlis, 2004; Ries et al.,

2011). The LAGEOS satellites are two passive spher-

ical spacecrafts tracked by the ground stations of the

International Laser Ranging Service (ILRS )(Pearl-

man et al., 2002) by means of the laser retroreﬂec-

tors mounted on the satellites. The addition of data

from LARES is expected to bring the accuracy to-

ward 1% (Ciufolini et al., 2013; Ciufolini et al.,

2012a). To reach that precision the spacecraft was

designed for reducing the non-gravitational perturba-

tions by means of a very high mass-to-surface ratio

(Paolozzi et al., 2015a). The particular material cho-

sen for obtaining a high density satellite, a tungsten

alloy, was challenging for manufacturing (Paolozzi

et al., 2009; Paolozzi et al., 2012c) and for modelling

the surface thermal-optical properties. Thermal test-

ing was needed for verifying that the laser retrore-

ﬂectors could work on a wide range of temperatures,

and in particular at the very high temperatures ex-

pected because of the optical properties of the bare

tungsten alloy (Paolozzi et al., 2010; Paolozzi et al.,

2012b). Indeed, even if higher temperature increases

the thermal thrust (Bosco et al., 2007; Ciufolini et al.,

2014), a passive thermal control by painting the satel-

lite body could have been even more dangerous for

the results because the thermo-optical properties of

the coatings were expected to change dramatically

during the operational life of LARES (Marco et al.,

2003; Pippin, 1995; Jaggers et al., 1993). Tests of

the LARES retroreﬂectors mounted in uncoated tung-

sten alloy breadboards were successfull and quali-

ﬁed the ﬁnal design. After the launch, the ILRS

Paris, C. and Sindoni, G.

Upgrade of the LARES-lab Remote Controllable Thermo-vacuum Facility - Lab Improvements for Remote Testing and e-Learning.

In Proceedings of the 8th International Conference on Computer Supported Education (CSEDU 2016) - Volume 2, pages 347-352

ISBN: 978-989-758-179-3

347

ground stations are receiving good reﬂected signals

from LARES, which demonstrates to be one of the

best laser ranging targets and the best test particle for

studying the gravitational ﬁeld of the Earth (Pavlis

et al., 2015a). LARES is also a useful addition to the

constellation of geodetic satellites for environmental

monitoring (Pavlis et al., 2015b). Once the satellite

was sent in orbit, the LARES-lab was used for fur-

ther measurements on the retroreﬂectors of LARES

and of other laser ranged spacecrafts (Paris and Neu-

bert, 2015). Because of the small dimensions, low

cost operation and the wide equipment of LARES-

lab, it is particularly suited for testing small pay-

loads ( Di Roberto et al., 2015a; Di Roberto et al.,

2015b) and microsatellites (Paris et al., 2015a; Paris

et al., 2015b). The tests sometimes require long du-

ration, for example when performing thermal cycling

in vacuum; when needed it was possible a basic re-

mote control of the tests (mainly to check the tem-

peratures), but the presence of at least one operator

was still needed. Furthermore the presence of a well

equipped space environment simulation facility in a

university is a great opportunity for teaching. How-

ever the limited space in the lab does not allow to ac-

commodate more than very few students at a time.

Also, sometimes the didactic activities needs to be

planned according to the time schedule of the uni-

versity courses to allow the students to participate.

Nevertheless the experience with university courses

that are using LARES-lab for lessons and seminars

showed a good appreciation both from professors and

students, and a good potential for increasing the di-

dactic activities. Therefore turning LARES-lab into

a remote controllable lab will be useful both for test-

ing and for teaching. However the two ﬁelds require

different capabilities. Indeed while it is acceptable

for a remote operator to have full access to the lab

equipment for a test, safety reasons require to limit the

access privileges for students. Feasibility of remote

labs for e-learning and teaching have been demon-

strated by a number of experiences worldwide (Casini

et al., 2001; Gustavsson, 2003; Aliane et al., 2007;

Eslami et al., 2008; May et al., 2013), however no

project based on thermo-vacuum testing was found in

the literature. The upgade of LARES-lab has been al-

ready discussed on a previous paper (Paolozzi et al.,

2015b); in the meanwhile some upgrades described in

the 2015 paper have been discarded or changed. In the

next sections the state of the project and the changes

made will be discussed.

2 SHORT DESCRIPTION OF

LARES-LAB

LARES-lab was designed with the goal of performing

optical tests in simulated space environment accord-

ing to the standard requirements of ESA for space

testing (ECSS, 2012; ECSS, 2002). The items to

be tested are put in a cubic vacuum chamber, where

the pressure can be maintained below 10

−6

mbar by

two pumps. The ﬁrst is a dry scroll pump (Ed-

wards XDS5) that brings the pressure below 2 mbar,

that is the limit required to start the turbomolecu-

lar pump (Edwards EXT255DX). The turbomolecu-

lar pump brings the pressure to the operational value.

The time to reach the ultimate pressure depends on

the volume and the materials of the item under test:

large surfaces and materials which have not been de-

gassed before the test need more time to reach the

ultimate pressure. A pressure gauge allow to mon-

itor pressure inside the chamber and is used to de-

cide when starting the turbomolecular pump. The tur-

bomolecular pump and the pressure gauge are con-

nected to a controller (Edwards TIC Instrument Con-

troller), which is connected to a personal computer.

A software (TIC PC monitor) is installed on the PC

for monitoring the pressure and the pump parameters.

The TIC PC monitor allows also to switch on and off

the turbomolecular pump. The dry pump, instead, is

not controlled by the TIC Instrument Controller. Fig-

ure 1 shows the vacuum chamber and some compo-

nents discussed in the paper. The vacuum chamber is

cubic. The length of the internal edge is 60 cm but

the presence of a cooling shroud on ﬁve walls short-

ens the length to about 55 cm. The cooling shroud is

composed of ﬁve copper plates cooled by an open cir-

cuit liquid nitrogen coil. Liquid nitrogen is fed from a

pressurized container. Temperatures down to -192 °C

can be reached when the liquid nitrogen valve is fully

open; partly closing and ﬁne tuning the valve allows

to set the temperature to a higher value. To simulate

the heath exchange toward a black body, the shroud

is painted with Aeroglaze Z307, a vacuum compati-

ble black paint having high absorbivity and emissivity

(ε = 0.89, α = 0.97) (Persky, 1999). Sun and Earth

radiation are simulated by means of a Sun simula-

tor with AM0 spectrum and a Earth infrared radiation

simulator disk. The Sun simulator lamp projects a

beam with AM0 spectrum and a constant power over

a 12x12 cm surface. The lamp is positioned outside

the chamber, and the light enters through a fused sil-

ica window with low absorption also in the ultraviolet

portion of the spectrum. The Earth infrared simula-

tor disk is positioned inside the chamber; temperature

on the disk is controlled by resistive heathers and set

CSEDU 2016 - 8th International Conference on Computer Supported Education

348

Figure 1: LARES-lab vacuum chamber. 1: turbomolecular pump; 2: pressure gauge; 3: TIC Instrument Controller; 4: liquid

nitrogen pipes; 5: electrical feed-throughs with multi-pin connectors; 6: inspection window.

to -18 °C , that is the blackbody equivalent tempera-

ture of Earth (Macdonald and Badescu, 2014). Resis-

tive heathers are used for additional thermal inputs.

The temperatures are recorded by platinum resistance

thermometers PT100. Two monitoring systems, a

HBM MGC-plus modular data logger and a PicoTech

PT104, allow to record data from up to 12 PT100

sensors (8 by the MGC-Plus and 4 by the PT104).

The same PC that controls the TIC Instrument Con-

troller also controls both the monitoring systems at

the same time. Three multi-pin feed-throughs (two

25-pins connectors and one 9-pin connector) provide

electrical contact with sensors, heathers and instru-

ments inside the chamber. A programmable power

supply is used to feed the heathers. Specimen under

test can be rotated by a one-degree-of-freedom ma-

nipulator. Optical testing in vacuum is possible by

means of a high quality optical window with a very

accurate surface ﬁnish (lambda/20 peak to valley at

632.8 nm).

3 REMOTE CONTROL OF

LARES-LAB

A Virtual Network Computing system (VNC) in-

stalled on the laboratory PC, allows simple control

of the turbomolecular pump and recording the tem-

peratures. We have tried different open source and

freeware software to ﬁnd the best solution for re-

mote control. For testing, any VNC is adequate but

for e-learning more control is needed over the stu-

dents privilege. We are still experimenting with Team

Viewer remote access software to conﬁgure safe ac-

cess to the lab. In the meanwhile, we are testing a sim-

pler conﬁguration for providing remote access during

a lesson to a room of students under the supervision

of a teacher.

4 UPGRADES OF LARES-LAB

In this section the upgrade with respect to what pro-

posed in (Paolozzi et al., 2015b) is described.

Upgrade of the LARES-lab Remote Controllable Thermo-vacuum Facility - Lab Improvements for Remote Testing and e-Learning

349

4.1 Dry Pump Control

The dry pump is not controlled by the TIC Instru-

ment Controller. The electric switch on the pump re-

mains in the ”on” or ”off” position when manually

operated. To have the possibility to remotely con-

trol the dry pump it is necessary to leave the switch

in the ”ON” position, then a single-board microcon-

troller (Arduino Uno) with AC 220 V relay module

controlled by the lab PC can be used to close or open

the power circuit of the pump.

4.2 Lights and Webcam

A strip of LED lights illuminates the vacuum cham-

ber. A webcam positioned on the door inspection win-

dow will show to the classroom the experiment inside

the vacuum chamber.

4.3 Robotic Arm and Manipulator

A small six degree-of-freedom robotic arm was pur-

chased for didactic activities and to gain experience

about servo-mechanism controls. The arm is con-

trolled by a 6 channel Pololu Micro Maestro con-

troller (Figure 2). The controller is connected with

a USB cable to the PC and can be remotely controlled

by the VNC system. In the previous paper we de-

scribed the planned remote operation of the manipu-

lator using a stepper motor coupled to the manipula-

tor drive; here we propose instead the use of a robotic

arm. The manipulator drive has several screw holes

that can be used to mount knobs. A simple knob has

been screwed on the drive and allows to move the ma-

nipulator using the robotic arm (Figure 3).

A second robotic arm to be mounted inside the

chamber is under study. The major difﬁculty being to

ﬁnd a device that can operate under vacuum.

4.4 Sun Simulator Screen

Another change to the previous plan regards the sys-

tem to cut the Sun beam. Initially we proposed a

sliding screen operated by a stepper motor. Learn-

ing from the experience gained with the robotic arm,

a more cost effective solution will be using a ser-

vomechanism operated by a second Pololu Micro

Maestro controller to move a smaller screen in front

of the Sun window. Using the same components and

control software for both the robotic arm and the Sun

screen allows an easier integration of the subsystems

on the remote controlled architecture.

Figure 2: The 6 channel controller for servomechanisms

(Pololu Micro Maestro). The controller is connected with

a USB cable to the lab PC.

Figure 3: The 6 degrees-of-freedom robotic arm operating

the manipulator drive using a simple knob. A better knob

will be created and mounted soon.

5 CONCLUSIONS

LARES-lab space environment simulation facility

was created for testing satellite components. Since

it is a university facility it is an important resource for

teaching. For fully exploiting the didactic potential of

LARES-lab, an upgrade of the facility for creating a

remote controlled testing and teaching platform is un-

der development. The plan presented in the 2015 pa-

per has been modiﬁed and some systems have been al-

ready installed and tested, including a robotic arm for

moving the manipulator and for gaining experience

for other remote controlled systems based on servo-

mechanisms. Further improvements are under study,

including the use of a second robotic arm inside the

chamber. Once the improved lab will be fully opera-

tional, the number of students that would have access

to the didactic experiments will be much increased.

CSEDU 2016 - 8th International Conference on Computer Supported Education

350

REFERENCES

Di Roberto, R., Nascetti, A., Paris, C., and Paolozzi, A.

(2015a). Optical payload for high-resolution Earth

imaging suitable for microsatellites. In 2015 IEEE

15th International Conference on Environment and

Electrical Engineering (EEEIC), pages 1863–1868.

IEEE.

Di Roberto, R., Paris, C., Nascetti, A., Paolozzi, A.,

and Graziani, F. (2015b). Assessment of a low-cost

multilayer insulation system for thermal control of

nanosatellites. In 66th International Astronautical

Congress. IAF.

Aliane, N., Martnez, A., Fraile, A., and Ortiz, J. (2007).

Labnet: A remote control engineering laboratory. In-

ternational Journal of Online Engineering (iJOE),

3(02).

Bosco, A., Cantone, C., Dell’Agnello, S., Monache, G. D.,

Franceschi, M. A., Garattini, M., Napolitano, T., Ciu-

folini, I., Agneni, A., Graziani, F., Ialongo, P., Lu-

cantoni, A., Paolozzi, A., Peroni, I., Sindoni, G., Bel-

lettini, G., Tauraso, R., Pavlis, E., Currie, D., Rubin-

cam, D., Arnold, D., Matzner, R., and Slabinski, V.

(2007). Probing gravity in NEO with high-accuracy

laser-ranged test masses. International Journal of

Modern Physics D, 16(12a):2271–2285.

Casini, M., Prattichizzo, D., and Vicino, A. (2001). The au-

tomatic control telelab: a remote control engineering

laboratory. In Decision and Control, 2001. Proceed-

ings of the 40th IEEE Conference on, volume 4, pages

3242–3247. IEEE.

Ciufolini, I., Monge, B. M., Paolozzi, A., Koenig, R., Sin-

doni, G., Michalak, G., and Pavlis, E. (2013). Monte

carlo simulations of the LARES space experiment to

test general relativity and fundamental physics. Clas-

sical and Quantum Gravity, 30.

Ciufolini, I., Paolozzi, A., and Paris, C. (2012a). Overview

of the LARES mission: orbit, error analysis and tech-

nological aspects. Journal of Physics. Conference Se-

ries, 354. conference 1.

Ciufolini, I., Paolozzi, A., Paris, C., and Sindoni, G.

(2014). The LARES satellite and its minimiza-

tion of the thermal forces. In 2014 IEEE Metrol-

ogy for Aerospace (MetroAeroSpace), pages 2014–5–

29/2014–5–30. IEEE.

Ciufolini, I. and Pavlis, E. C. (2004). A conﬁrmation of the

general relativistic prediction of the Lense-Thirring

effect. Nature, 431:958–960.

Ciufolini, I., Pavlis, E. C., Paolozzi, A., Ries, J., Koenig, R.,

Matzner, R., Sindoni, G., and Neumayer, H. (2012b).

Phenomenology of the Lense-Thirring effect in the so-

lar system: measurement of frame-dragging with laser

ranged satellites. New Astronomy, 17:341–346.

ECSS (2002). ECSS-e-10-03a, space engineering: Test-

ing. , European Cooperation for Space Standardiza-

tion - ECSS Secretariat ESA-ESTEC Requirements

and Standards Division Noordwijk, The Netherlands.

ECSS (2012). ECSS-e-10-03a, space engineering: Test-

ing. , European Cooperation for Space Standardiza-

tion - ECSS Secretariat ESA-ESTEC Requirements

and Standards Division Noordwijk, The Netherlands.

Eslami, A., Williams, A., Lapat, L., Krauss, K., and Osareh,

A. R. (2008). A remote control project to enhance un-

dergraduate students interest and knowledge in indus-

trial automation. In Proceedings of IAJC-IJME Inter-

national Conference.

Gustavsson, I. (2003). A remote access laboratory for elec-

trical circuit experiments. International Journal of

Engineering Education, 19(3):409–419.

Jaggers, C. H., Meshishnek, M. J., and Coggi, J. M. (1993).

Thermal control paints on ldef: Results of m0003 sub-

experiment 18. In LDEF: 69 Months in Space. Part

3: Second Post-Retrieval Symposium; p 1075-1092.

NASA. Langley Research Center.

Macdonald, M. and Badescu, V. (2014). The International

Handbook of Space Technology. Springer.

Marco, J., Bhojaraj, H., and Hulyal, R. (2003). Evaluation

of thermal control materials degradation in simulated

space environment. In Fletcher, K., editor, Materials

in a Space Environment, volume 540 of ESA Special

Publication, pages 359–366.

May, D., Terkowsky, C., Haertel, T., and Pleul, C. (2013).

Bringing remote labs and mobile learning together.

International Journal of Interactive Mobile Technolo-

gies – iJIM, 7(3):54–62.

Paolozzi, A. and Ciufolini, I. (2013). LARES succesfully

launched in orbit: satellite and mission description.

Acta Astronautica, 91:313–321.

Paolozzi, A., Ciufolini, I., Felli, F., Brotzu, A., and Pilone,

D. (2009). Issues on LARES satellite material. In 60th

International Astronautical Congress - IAC, Daejeon,

Republic of Korea, number IAC-09.C2.4.5. IAF.

Paolozzi, A., Ciufolini, I., Paris, C., and Sindoni, G.

(2015a). LARES, a new satellite speciﬁcally designed

for testing general relativity. International Journal of

Aerospace Engineering, Volume 2015:9 pages. Arti-

cle ID 341384.

Paolozzi, A., Ciufolini, I., Paris, C., and Sindoni, G.

(2015b). Lares-lab: A thermo-vacuum facility for re-

search and e-learning - tests of lares satellite compo-

nents and small payloads for e-learning. In Proceed-

ings of the 7th International Conference on Computer

Supported Education, pages 467–474.

Paolozzi, A., Ciufolini, I., Paris, C., Sindoni, G., and Spano,

D. (2012a). Qualiﬁcation tests on the optical retro-

reﬂectors of LARES satellite. In 63rd International

Astronautical Congress IAC 2012, Naples, Italy. IAF.

Paolozzi, A., Ciufolini, I., Paris, C., Spano, D., Battaglia,

G., and Reinhart, N. (2012b). Thermal tests on

LARES satellite components. In 63rd International

Astronautical Congress IAC 2012, Naples, Italy. IAF.

Paolozzi, A., Ciufolini, I., Schirone, L., Peroni, I., Paris,

C., Spano, D., Sindoni, G., Vendittozzi, C., Battaglia,

G., and Ramiconi, M. (2010). Tests of LARES cube

corner reﬂectors in simulated space environment (pre-

liminary results). In 61th International Astronautical

Congress - IAC.

Paolozzi, A., Ciufolini, I., and Vendittozzi, C. (2011). En-

gineering and scientiﬁc aspects of LARES satellite.

Acta Astronautica, 69:127–134.

Upgrade of the LARES-lab Remote Controllable Thermo-vacuum Facility - Lab Improvements for Remote Testing and e-Learning

351

Paolozzi, A., Ciufolini, I., Vendittozzi, C., and Felli,

F. (2012c). Material and surface properties of

LARES satellite. In 63rd International Austronauti-

cal Congress IAC 2012, Naples, Italy. IAF.

Paris, C. and Neubert, R. (2015). Tests of LARES and

CHAMP cube corner reﬂectors in simulated space

environment. In 2015 IEEE Aerospace Conference,

pages 1–9. IEEE.

Paris, C., Parisse, M., and Allawi, W. (2015a). Thermovac-

uum tests on TIGRIsat structure: Validation of the

thermal model of a 3U cubesat. In 2015 IEEE Metrol-

ogy for Aerospace (MetroAeroSpace), pages 160–165.

IEEE.

Paris, C., Parisse, M., Nascetti, A., Cica, R., and Salman,

N. (2015b). The TIGRIsat camera. a nanosatellite op-

tical payload for detecting dust and sand storms. In

2015 IEEE 15th International Conference on Envi-

ronment and Electrical Engineering (EEEIC), pages

1605–1610. IEEE.

Pavlis, E., Ciufolini, I., Paolozzi, A., Paris, C., and Sindoni,

G. (2015a). Quality assessment of LARES satellite

ranging data: LARES contribution for improving the

terrestrial reference frame. In 2015 IEEE Metrology

for Aerospace (MetroAeroSpace), pages 1–5. IEEE.

Pavlis, E., Sindoni, G., Paolozzi, A., and Ciufolini, I.

(2015b). Contribution of LARES and geodetic satel-

lites on environmental monitoring. In 2015 IEEE 15th

International Conference on Environment and Electri-

cal Engineering (EEEIC), pages 1989–1994. IEEE.

Pearlman, M., Degnan, J., and Bosworth, J. (2002). The

international laser ranging service. Advances in Space

Research, 30:135–143.

Persky, M. J. (1999). Review of black surfaces for space-

borne infrared systems. Review of Scientiﬁc Instru-

ments, 70(5):2193–2217.

Pippin, H. G. (1995). Analysis of materials ﬂown on the

long duration exposure facility: Summary of results

of the materials special investigation group. Techni-

cal report, NASA. Boeing Defense and Space Group,

NASA CR.

Ries, J. C., Ciufolini, I., Pavlis, E. C., Paolozzi, A.,

Koenig, R., Matzner, R. A., Sindoni, G., and Neu-

mayer, H. (2011). The earth’s frame-dragging via

laser-ranged satellites: a response to ’some consider-

ations on the present-day results for the detection of

frame-dragging after the ﬁnal outcome of GP-B by io-

rio l.’. Europhysics Letters, 96(3).

CSEDU 2016 - 8th International Conference on Computer Supported Education

352