OHB-FACTORS first meeting 2018-08-27

Japan (Y Saito from ISAS, M Hirahara from Nagoya U)
OHB (Fredrik Sjöberg, Gierth Olsson, Peter Rathsman, )
SNSA (Johan Köhler, Ronnie  Lindberg)
KTH (Nickolay Ivchenko)
IRF (Yuri Khotyaintsev from Uppsala, Yamauchi from Kiruna)

9:30-12:00 
(1) OHB presentations for general activity
- Have built up to Max 400 kg
- Have build subsystems for ESA spacecraft
- Provide attitude control(AOCS), propulsion(CP&EP), small satellite technology
- Cleanroom ISO class 8
- In-house control center (for InnoSat etc)
- Experience in Moon mission with electric propulsion (SMART-1 in 2003)
- Experience in formation flight with short distance (PRISMA in 2010)
- Now building series of Innosat, with #1 (Mats) nearly ready

(2) Hirahara/Saito presentation of FACTORS formation flying
- FACTORS (two nearly identical satellites of 160-170 kg wet mass each)
   - Horizontally separated by 1-100 km
   - 2026-2027 Launch, with final proposal to be submitted 2020-2021.
   - perigee 300-400 km x apogee 4000 km
   - Sun-synchronous 104.5° inclination (noon-midnight orbit)
   - eclipse maximum 40-50 min

(3) OHB Presentations of Innosat/Prisma
- Innosat 
   - Innosat-1 (MATS) launch Dec. 2019 (waiting for Piggyback opportunity), 
   - 50 kg without propulsion (20 kg for science payload),
   - 3-axis stabilized with reaction wheels, star tracker, and GPS
   - 0.01 deg. for determined attitude
   - S-band 5 Mbps/ X-band >100Mbps
   - 28 V bus, 5 V for data handling system
   - Safe hold mode by magnetometer for sun-pointing without spin motion
   - Launcher side provides satellite separation device/adapters
   - Seeking low-cost subcomponents every time (inc. Canada, South Africa)
   - All Innosat launched in cold mode
   - Initial critical operation from the OHB building remotely using ESRANGE
- PRISMA 
   - Autonomous formation flying within 1 km distance and autonomous rendezvous
   - Inter-satellite link (but very slow)
   - 3-axis stabilized Two sub-satellites, passive Tango of 40 kg and active Mango of 145 kg including 15 fuel with 3 propulsion system > 200 m/s Delta-V
   - Thrusters of 1 N and (hundred)milli-N micro
   - Separation distance of 2 m and 32 km at min. and max. at 550 km altitude

(4) Discussion on InnoSat-FACTORS formation flight
- Techical summary
   - No special consideration from SNSA side (i.e., InnoSat is normal competition)
   - Innosat-3 A/O is still unclear due to weak SEK (SNSA hopes 2020-2021)
   - InnoSat formation to be horizontally rather than vertically
   - Innosat flies without propulsion and control is done only for FACTORS
   - Nominal time for InnoSat is 1 year
   - Perigee = 400 km for the first year, and FACTORS decreases perigee afterward
   - Allowed mass for InnoSat depends on the capability of new launcher 
   - With extra mass allowance, spot-sheilding solves the radiation problem
- Priority of the feasibility study to fit InnoSat into FACTORS
   1a. Radiation harness for 1 year
   1b. Buttery for eclipse (< 50 min): to survive only spacecraft without observation
   2.  Propulsion
- Logistic summary
   - All improvements are possible depending but they costs extra
   - Actual specification for InnoSat 3 is determined by SNSA, and there is no guarantee that 1a, 1b to be implemented.
   - FACTORS final proposal must not rely on InnoSat 
     (InnoSat adds extra on already good science with only two spacecraft)
   - FACTORS proposal should address three cases regarding Innosat, no Innosat, Innosat without propulsion, Innosat with propulsion.
   - When FACTORS phase starts, OHB personal is ready to attend necessary meeting

(5) Action items
- Viewgraph exchange between FACTORS (Hirahara) and InnoSat/PRISMA (OHB)
- Orbit information of FACTORS to OHB
- Radiation dose estimate of FACTORS to OHB
- Uplink and downlink information of FACTORS to OHB to make common operation
- Mass and size allowance for InnoSat when lifting together with FACTORS to OHB as soon as the new launchers ability is fixed.


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estimate should be sent to OHB from Hirahara.
Innosat with/without propulsion system for reducing the cost.
Innosat can keep 400 km as perigee if there is no suitable science instruments for less than 400 km
Innosat as spinner for DC electric field observations?


proposal in 2021?) or 4 for FACTORS
F-mission for Innosat-4? In 2027-8?
First proposal by 25 Oct., 2018
Four months for real proposal
Total weight 1 ton at L2


KTH meeting
14:15- at KTH
14:15- introduction of KTH by Marklund
MATS, PI is a professor of Univ. Stockholm
PRISMA, Innosat
SPIDER, SEAM&MIST
EISCAT_3D
CLUSTER II, MMS (Electric field antennas, DC/DC board, electronics)

A/I of Swedish side
Spinning Innosat to ask OHB
Additional science by Innosat for both spinner or non-spinner
Review of FACTORS science subjects
Hardware contributions between Sweden and Japan
One without FACTORS or another proposal with FACTORS for Innosat-3?
Other contribution to FACTORS?

A/I of Japanese side
Radiation environment estimate
Other contribution to Innosat?