ARISS International Teleconference
Tuesday July 17, 2007 11:15 UTC (7:15 am ET)
Participants:
Frank Bauer
Rosalie White
Mark Steiner
Larry Agabekov
Keigo Komuro
Masanobu Tsuji
Dave Larsen
Daniel Lamoureux
Ken Nichols
Gaston Bertels
Lou McFadin
Keith Pugh
Graham Shirville
Miles Mann
Ken Pulfer
Carol Jackson
Bill Boston
Steve Ponder (for Kenneth)
Interpreter, Olga Frumkin
Not Present:
Robin Haighton
Kenneth Ransom
Tadeu Fernandes
Sergey Samburov
Carlos Eavis
Matt Keil
ARISS I Agenda:
NOTE: Frank’s is having problems with his Comcast email.
Administrative Session
1. TIM outcomes, Presenter: F. Bauer
Volume and crew time issues
Computer
Kenwood & Ericsson issues – resolutions
ARISS-I Meeting, Status
The U.S. team just found out that the Ericsson radio system in the FGB had been stowed away in the February timeframe due to space limitations onboard. Frank was able to have discussions with Mr. Poleschuk/RSC-Energia and Carlos Fontanot/NASA regarding the future of ARISS. There are getting to be extreme limitations onboard regarding volume, both operational and stowage, as well as crew time availability. Mr. Poleschuk said that ARISS will not be able to get any more items in addition to what is already onboard the FGB and Service Module. That means that any radio systems we send up need to be no larger than what is already up there, and that we will need to bring down something in its place. Given the lack of available crew time, it would make sense to have the systems be as autonomous as possible.
There is general agreement that ARISS needs and will get a dedicated computer, and the U.S. side is working on the details.
A Technical Interchange Meeting (TIM) was held in Houston, TX July 9 – 13, 2007 with the U.S. team and Sergey Samburov. Highlights include:
a) Swap out the D700 with the flight spare rather than re-programming
b) Bring down the 70 cm Ericsson and replace it with the Yaesu FT-817.
c) Initial plans were made to utilize the SuitSat-2 design in a Phase 3 system. It would be a software defined radio that would be flexible enough to have unattended operations under ground control and still be available for crewmembers. The user interface would be flexible enough to be simple to operate for crewmembers who just want to talk and yet handle crewmembers who want to get more involved in ham operations.
Question was raised as to space limitations in the Columbus module. There has been no discussion with the space agencies as to any limits at this point, but it would be a good idea to get it up there quickly before it fills up.
2. SuitSat Certificates, Presenter: F. Bauer
No status to report at this time.
3. SuitSat-2 CD-ROM discussion, Presenter: F. Bauer
US team has received an official fax from RSC-Energia that they will be working on flying SuitSat-2, so the effort is moving forward on an official capacity. The working date for deployment is late May 2008, with hardware delivery set for mid-January. It will commemorate the 150th birthday of K. Tsiolkovsky and the 50th anniversary of the launch of Sputnik-1. This will be an official experiment, as SuitSat-1 was.
ARISS will continue to exploit the educational opportunities presented by SuitSat-2.
Frank, Rosalie, Carol, and Mark will develop a summary of the TIM minutes to go out on ARISS-I.
4. SuitSat-2 voice recordings, Presenter: F. Bauer
There will be an extensive voice recording capability, much beyond that of SuitSat-1. Frank will be getting out details on the messages to the delegates shortly, as well as a plan for school submissions.
5. New Business (administrative only)
None.
General Session
6. SuitSat-2 Status, Presenter: L. McFadin
Discussions at the TIM have furthered the details of the circuit designs, and prototypes have been built. Fabrication of the flight units will begin shortly.
SuitSat-2 will have several changes and improvements over SuitSat-1:
a) antenna design – the antenna and RF system will be shipped as an assembled unit, to reduce amount of crew involvement
b) RF power – 1-2 watts output
c) CW ID – always on. Lou McFadin has come up with the idea of sending on a CW beacon a list of callsigns of hams who have contributed to amateur satellites currently and in the past.
d) solar panels and batteries for continuous power through end of mission. Modes have been developed such that, as more power is available, more modes will be available.
e) 4 experiments with data telemetered down
f) linear crossband repeater (70 cm up/2 m down)
g) packet operations h) SSTV – 4 cameras will be used to gather pictures to send down
7. Columbus Module Status, Presenter: G. Bertels
Gaston will send to Carol text of his presentation for inclusion in these minutes. [The presentation has been appended.]
ARISS-32 is at Goddard for SiO2 coating. Gaston would like Goddard to do whatever RF characteristics testing can be accomplished.
More RF testing will be performed on the antennas that are still in Europe.
ARISS v3 antennas were tested by ESTEC with some anomalies. Some delaminations occurred where rivets were removed from the v2 design at ESA’s request. V4 antennas will be developed and tested in Poland for flight.
8. New business
There will be a technical discussion on what needs to be reconfigured on the D700 before the new unit is flown.
The next ARISS International Team meeting will be held on Tuesday, August 21, at 11:15 UTC.
Respectfully submitted,
Mark Steiner, K3MS, for the ARISS Team
ARISS 4x antennas
- The ARISS-3x antennas were tested by ETS at ESA/ESTEC in Noordwijk, the Netherlands. Thermal tests under vacuum revealed some structural weaknesses and ESA requested improvements.
- One antenna (ARISS-32) was sent to Mark Steiner. The intent is to allow Goddard lab to examine the proper way to apply SiO2 coating to the antennas. The ARISS-32 antenna can also be used for checking the electromagnetic properties of the design.
- The three other ARISS-3x antennas are now back at Wroclaw University. One of them can be used for efficiency testing, which I will propose to the ARISS-Europe team.
- The Wroclaw team examined the antennas. No important parts have suffered in any way. Two delamination areas (outer laminate detached from foam) occurred in the outer regions where rivets were used for the ARISS-2x antennas. ESA engineer requested to remove the riverts in ARISS-3x antennas.
- The existing antennas can be strengthened with a few rivets and submitted to tests again. Repair of the ARISS-35 – the one with the delamination – is no problem either.
- We will propose to return the amended existing antennas to ETS for tests. If they pass the tests they should be qualified, accepted and installed. This cannot be done before August because of ESA personnel holidays.
- Incidentally, preliminary analysis made by ESA showed that with modification of the foam form in the ARISS-3x design and with use of the ARISS-3x set of materials, it is likely possible to develop antennas capable to pass thermal tests. However, there is no time to prove and qualify the new perforated foam form in a very short term at ESA.
- Therefore, taking into account time constraints and guidance given by ESA, 3 new antennas (ARISS-41, ARISS-42, ARISS-43) will be developed and manufactured in Wroclaw. The manufacture process shall be completed in August.
- To ensure compliance of thermal properties, around 40 specimens of sandwiches (mostly50x200x8 mm) are prepared by Wroclaw team. They will undergo tests at ESTEC to open green light for assembly of the ARISS-4x antennas.
- On advice of space industry veterans working at ESA, to ease mechanical stress at very low temperatures due to different thermal expansion coefficients, the same material (RO 4003C laminate) will be used for both active layers of the antenna sandwich. Moreover, gluing facesheets to foam will be done at room temperature.
- Silicone glue will be used for ARISS 4x antennas and will perform better at such low temperatures than the cyano esters used up to ARISS-3x.
- Initial computer simulations predicted lower electromagnetic properties than with the previous design, but still sufficient to cover the intended usage on L- en on S-band. After extensive studies, the computed properties as on 12 July are again very good. They must be confirmed by measurements of models developed now. The only drawbacks we could not have improved much after two weeks of studies are: quality of the circular polarization (Axial ratio is ~2 dB worse) and a level of LHCP polarization with respect to the RHCP is higher (used to be 40 dB or better, now it is 20dB). Therefore it would be preferable that the amended ARISS-3x antennas be accepted.
- Concerning atomic oxygen, Wroclaw will purchase CV-1144 protection material and examine. If succesfull, coating at Goddard would possibly not be needed. This is an open study.
- If tests at ESTEC are positive and the antennas pass the qualification procedures, installation will be done at KSC in September or October.
- To cover the costs of the ARISS 4x antennas manufacturing, Pawel Kabacik has applied to the Polish Ministry for Scientific and Technological Research (15k euro) and to the Polish Science Foundation (40k euro). In principle, these fundings are subject to equivalent funding from elsewhere. Pawel has inquired at the Polish National Radio Amateur Society. We will continue the search for funding.