Q & A - Call for missions 2021
Call for a Medium-size and a Fast mission opportunity in ESA's Science Programme
Questions and Answers
Q8: Is it possible to plan with an Ariane 64 launcher as baseline? If so, could you specify the impact on cost compared to Ariane 62?
A8: It is not formally forbidden to consider Ariane 64. The sole reason for discarding Ariane 64 is the cost envelope, which would require to shrink the space segment cost envelope (and likely the scientific capabilities accordingly) to stay in budget. The use of Ariane 64 would raise the launcher cost fraction from ~16% to ~30%.
Q7: Could you provide data on the launch mass vs. v_inf for Ariane 62 and Ariane 64?
A7: The technical annex provides some known Ariane 62 performance vs Vinf (Table 1). For Ariane 64 preliminary values can be obtained by scaling the data on the table according to the ratio of performance between A62 and A64 in the case for 2.5 km/s presented in the Ariane User Manual (available from Arianespace website). The scaling ratio is 6900/2600 = 2.65.
However, it shall be stressed that most data are available for a limited range of launch declinations (around zero deg). If higher declinations are required, the above scaling is not valid and specific analyses need to be performed.
Q6: Is there a limitation on the mission duration (other than cost)?
A6: No, however see question 8.
Q5: Could you provide an order of magnitude on annual mission cost for electric/chemical transfers?
A5: There is no generic answer. Transfer cost depends on the complexity of the mission profile (swing-by's and their criticality), hibernation or not, use of SEP (requiring continuous hands-on adjustment of transfer), navigation issues (e.g. ephemerides not well known) etc. However, transfer operations cost is not a small fraction of the nominal costs during the science operations phase, and a reasonably conservative assumptions is to consider the operation costs during transfer are comparable to nominal yearly operation costs. Refinements could be considered for the Phase 2 proposals.
Q4: As per the call, 3 pages of the Phase 1 proposal should describe the science case and the technical case of the mission. What about references? Do these count towards the 3 page limit (in each case) or should references, for instance, be placed in an Appendix?
A4: References can be included as an Appendix, and will not be counted against the proposal page limit.
Q3: Should the proposals contain a detailed mass/power budget at this stage? Or would some broad indication of the mass/power needs be sufficient?
A3: For Phase 1 proposals, a rough-order-of-magnitude estimate is sufficient for both mass and power.
Q2: At the M & F Call briefing on 13 January, we were instructed to inform ESA of any possible International collaborations. Can you please advise on how we should include international collaboration in our proposal?
A2: Thank you for informing us of a possible International collaboration. As the collaboration is not yet agreed, we advise to submit the Phase 1 proposal assuming a European-only mission. During the period between Phase 1 and Phase 2 submissions, we will work with our International partners to confirm their willingness to collaborate on the proposed missions.
Q1: About Ariane 62 launch performance: What would it be on a polar ~2000x6500 km orbit? I don't think I can infer this information from the technical Annex of the Call which gives a 7t capability on a polar 900 x 900 km orbit.
A1: There are no Ariane 62 performance data readily available for polar HEO orbits as these are very specific. However, we do not anticipate any feasibility issue with Ariane 62 for the orbit you are contemplating (polar, perigee and apogee heights around 2000 km and 6400 km respectively). The performance of Ariane 62 will be compatible with the recommended maximum mass of 1500 kg for the M-class mission for this orbit.
Last update: 3 February 2022