The Astro Space Center of Lebedev Physical Institute hosted the 28th International RadioAstron Meeting on November 18-21 2003. The agenda of the meeting and the list of participants are presented in the Appendixes to the Minutes.

Working Group Meetings on Tuesday, November 18.
The Working groups held meetings to review their activities and to develop plans for future cooperation. Six working groups were created at the previous RadioAstron meeting (September 2002): On-board Science Payload, Tracking Stations, Mission Operations, Ballistic and Navigations, Correlators and Data Processing, and Science Program.

The Working Group on Mission Operations decided to use the following time-line for its activities:
April 2004 - to develop an approach or method of obtaining observing time from ground radio telescopes by contacts with observatories and VLBI networks;
October 2004 - to prepare call to the radio astronomy community for proposals and participation in 6-12 key science programs (KSP) decided by the mission for the first year of science operations;
November 2004 - January 2005 - evaluation of the KSP-proposals by the Science Review Committee;
February 2005 - to submit 6-12 KSPs to GRTs and VLBI networks together with the proposal for in-orbit checkout support.

Members of the Science Program Working Groups presented several reports on the prospective objects and some KSPs to be undertaken by the RadioAstron Mission. It was recommended to formulate 6-12 key science programs to be discussed at the next meeting.

It was felt that the working group activity has been rather low, mainly because of lack of funding at foreign institutions.

Open Session of the 28th International RadioAstron Meeting on Wednesday, 19 November.
The Wednesday meeting consisted of 23 presentations of specific reports relating to the RadioAstron Mission and covering the status of mission development and future plans. Participants of the meeting recognized the dramatic progress of the work during the last year and particularly the following achievements: 1) the engineering unit of the satellite service module was completed at Lovochkin except for a few link-related items; 2) the antenna has been assembled and has been set up at Puschino for detailed system and performance testing to be finished in December 2003. The overall planning called for assembly of the flight modules in early 2005 and all necessary testing and development to be finished by 2004. In 2004 the payments will be placed for the launcher.

Closed RISC Session on Thursday, 20 November, for RISC members and special invites.
The issue of the provisions for the ground stations (Pushchino, Tidbinbilla, & Green Bank) and the requirements for recording and correlation were discussed extensively. During a special visit of Mr Phillip Cleary from the NASA Russia Office, the meeting was able to reiterate the request made for NASA support with equipment transfer to the three ground stations and for support with correlation efforts. It was stated that currently planned NASA support with the transfer of equipments from US tracking stations to Pushchino and funding of modifications and operations of Tidbinbilla tracking station would not be sufficient for RadioAstron Mission success in this area. The following priorities in potential NASA support were formulated: a) funding of development and future operations of the Green Bank tracking station; b) transfer of equipment to Pushchino; c) funding for operation of the Tidbinbilla tracking station; d) funding of RadioAstron related operations of the NRAO VLBA correlator; e) funding of support from the Jet Propulsion Laboratory (JPL) for orbit determination. It was also stated by the representatives of NRAO that without financial NASA support, the NRAO participation in RadioAstron Mission would be inconceivable if not impossible.

Long discussions were held on the definition of RadioAstron Mission profile as facility against discovery mission. A double status would probably be possible. No consensus was reached on the matter, and the discussion was tabled until the next meeting.

A discussion ensued on the issue of the high orbit. Most of the RISC members could support the 350.000 km orbit at this time. The EVN representatives objected to the procedures followed in this matter because previous recommendations of the RISC clearly rejected any high orbit for reasons of scientific return. Serious concerns were raised by several RISC members whether all technical issues were solved to ensure adequate system performance in a high orbit with particular regard to the link margins, and the S/N values and phase stability on the return path.

On the Space H-maser (SHM) most participants considered this to be a luxury item that was not considered essential for the mission. On the other hand, it would be a useful device to ensure longer integration times and a better sensitivity at 22 GHz. It was generally agreed that in the case of additional ESA funding, this should be used for the 6cm receiver and for data processing at JIVE. N. Kardashev agreed to consider this advise, but insisted that the H-maser is needed for the RA Mission because under real conditions it will essentially increase the reliability of SRT synchronization. In addition, the SHM will allow an increase of the general sensitivity and will give higher accuracy in the orbit determination. He informed the RISC members that some efforts have been already undertaken by ROSAVIAKOSMOS officials in order to discuss the matter at the oncoming ROSAVAKOSMOS/ESA meeting in January 2004.

An informal agreement was made at the meeting to accept the 350.000 km orbit but that no further efforts are initiated to obtain funding for a Space H-maser.

Considering past experience, RISC agrees that it should consider itself as an advisory committee. However, the RISC recommends that ASC should consider all advice carefully and should provide timely motivated reasons when not taking into account the recommendations of the RISC. In this matter the RISC is unique in that the Mission has considerable foreign input but that there is no mechanism for external steering.

Because the membership of the RISC was not complete at the meeting, it was considered that the decisions and recommendations made at this meeting are not binding.

As a result of all discussions RISC has formulated several unresolved critical-path issues that must be addressed immediately: (a) space-qualified receivers, (b) Tracking and Data Acquisition (TDA) stations, and (c) Data Correlation. (a) There are, at present, no space-qualified flight receivers for any band. It appears that a qualified 1.3 cm receiver will be available by the end of 2004, but no realistic plan was presented for obtaining either a 6 or 18 cm receiver. These must be treated as urgent questions, to be resolved immediately. (b) The availability of TDA stations is a serious unresolved issue, which depends upon the completion of an amended RSA-NASA agreement. If this is not completed soon, the mission will be in serious difficulty. (c) Plans for data correlation will have to be specified. At present the ASC has a one-baseline disk-based system for RadioAstron tests. This correlator will be developed into a 4 stations disc-based correlator by early 2006. Hence, the participation of NRAO VLBA correlator and an upgraded Canadian correlator (or JIVE correlator) in the RadioAstron mission would be very desirable. Settling the issue of correlation is an urgent question. In addition, the issue of data compatibility is very important.

RISC has approved the following list of its current membership:

1. Alain Maurissen     Neuchatel Observatory, Switzerland
2. Anton Zensus     MPIfR, Germany
3. Bernard Burke     MIT, USA
4. David Jauncey     CSIRO, Australia
5. Hisashi Hirabayashi     ISAS, Japan
6. Ken Kellermann     NRAO, USA
7. Kornelis Van Klooster     ESA (observer)
8. Leonid Gurvits     JIVE, the Netherlands
9. Leonid Lytvynenko     IRA, Ukraine
10. Mikhail Popov     ASC, Russia (secretary)
11. Nikolay Kardashev     ASC, Russia (co-chairman)
12. Seppo Urpo     HUT, Finland
13. Sergey Likhachev    ASC, Russia
14. Subramaniam Anathakrishnan     TIFR, India
15. Vladimir Andreyanov     ASC, Russia
16. Vladimir Serebrennikov     LA, Russia
17. Vyacheslav Slysh     ASC, Russia
18. Wayne Cannon     CRESTECH, Canada
19. Willem Baan     ASTRON, the Netherlands (co-chairman)
20. Xiaoyo Hong     SHAO, China

RISC has appointed W. Baan to be a co-chairman on the following two years (2004-2005) and has appointed M. Popov to serve as a RISC secretary.

In general the RISC members were very positive about the progress made and formulated a series of actions that could help raise the profile of this mission in the radio astronomy community and that could assist the ASC group in managing certain issues.

The following action items have been formulated:

• To assign RISC secretary M. Popov to serve as a central communication person in order to overcome general lack of communication between the ASC and foreign participating institutions.
• ASC project leadership to continue contacts with the EVN to establish an understanding of the status of 6-cm on-board receiver and to prepare cooperation agreement (MOU) (April 2004).
• ASC to recommunicate with the representatives of 18-cm and 1.35-cm on-board receiver builders in Australia and in Finland in order to establish the status and possible usage of the receivers in future mission development and flight operations (April 2004).
• ASC to develop contingency plan for the case that no NASA financial support for US tracking stations and correlators is provided (a worst scenario), and to present the information of this plan to the next meeting.
• ASC to facilitate its activities to provide full information on the mission parameters and the scientific profile to the international radio astronomical community, and in particular, to prepare presentations at the EVN symposium to be held in Spain (Granada/Toledo, September 2004).
• W. Cannon to investigate possibility to use Penticton correlator with the MkV disk recording system (April 2004).
• K. Kellerman and L.. Gurvits to review the content of the "Red Book" (also present at the RadioAstron Web page) and to present their comments and corrections (January 2004).
• RISC members to present their comments on the "RISC Terms of Reference" (April 2004).
• ASC to organize teleconferences on January 29 and March 11 at 14:00 UT.
• Next RadioAstron Meeting may be held in Dwingeloo on April 20-21.
• Next RadioAstron Meeting in Russia will be held in Moscow on November 2-3 2004.

Appendix I: Agenda of the meeting

Appendix II: List of participants