I would like to nominate the Mission Extension Vehicle as a potential non-CRS mission.
(from prior thread:)I would like to nominate the Mission Extension Vehicle as a potential non-CRS mission.It's a GTO/GSO launch, as many of its lucrative sats are, which fly mostly on F9, so it would likely not fly on Antares, for same.
(from prior thread:)I would like to nominate the Mission Extension Vehicle as a potential non-CRS mission.It's a GTO/GSO launch, as many of its lucrative sats are, which fly mostly on F9, so it would likely not fly on Antares, for same.
MEV-1 already has a paying customer in GSO, SES IIRC, and is scheduled for a Q4 Proton launch. I expect future GSO missions will also use an LV that can send MEV to at least GTO.
Antares only has the oomph to push MEV to LEO. Since I don't have many MEV specs, what follows is complete speculation. Potentially an MEV variant can replace Cygnus's primary propulsion as a reusable, space-based, final stage. The theoretical gain is a cheaper Cygnus with more cargo capacity. Another possibility would be expanding the range of orbits accessible to cubesats travelling via ISS. An MEV could potentially chase down an astronaut drifting away from ISS.
(from prior thread:)I would like to nominate the Mission Extension Vehicle as a potential non-CRS mission.It's a GTO/GSO launch, as many of its lucrative sats are, which fly mostly on F9, so it would likely not fly on Antares, for same.
MEV-1 already has a paying customer in GSO, SES IIRC, and is scheduled for a Q4 Proton launch. I expect future GSO missions will also use an LV that can send MEV to at least GTO.
Antares only has the oomph to push MEV to LEO. Since I don't have many MEV specs, what follows is complete speculation. Potentially an MEV variant can replace Cygnus's primary propulsion as a reusable, space-based, final stage. The theoretical gain is a cheaper Cygnus with more cargo capacity. Another possibility would be expanding the range of orbits accessible to cubesats travelling via ISS. An MEV could potentially chase down an astronaut drifting away from ISS.
Cygnus VV for the ISS is qualified to work in the KOS.
What allows the MEV to function is a large solar array from the long lived electric propulsion. The vehicle can be maneuvered to avoid antenna's and panels on a comsat.
But on the ISS this might not be such a good idea for prox ops. The array needed is too large.
Use as a reusable bus for handoff of a passive payload is something Lockheed's CRS-2 proposal also had (as well as a similar scheme reusing Soyuz (possibly also Progress), which has excess props on the vehicle for an earlier proposal). This wasn't appealing because of the need in the the CONOPs for multiple vehicle rendezvous/docking to deliver supplies, as opposed to the single dock/undock to complete the mission, thus too high of a risk to complete the mission (what NASA said).
Also, the need for propulsion for Cygnus is different than MEV. Enhanced is about 12,000lbs, about 3x more than MEV can handle. And the point of MEV is for station keeping, not to phase/deorbit a cargo container, which requires considerably more thrust for a shorter time (has to enter/clear the KOS in a relatively short time).
Here's where you could use a 10x scaled up MEV - you could use it to gradually move a Cygnus sized payload back and forth between low earth orbit and cislunar destinations. However, this would require a larger LV than Antares to launch it.
Orbital ATK Receives Order for Second In-Orbit Satellite Servicing Vehicle
Intelsat Commits to Second Life Extension Mission
Dulles, Virginia 4 January 2018 – Orbital ATK (NYSE: OA), a global leader in aerospace and defense technologies, today announced it has been awarded a contract for a second Mission Extension Vehicle (MEV-2). The vehicle was ordered by Intelsat S.A. to provide life extension services for an Intelsat satellite. Orbital ATK is now producing MEV-1, the industry’s first commercial in-space satellite servicing system, for Intelsat with launch scheduled for late 2018. Under this new agreement, Orbital ATK will manufacture, test and launch MEV-2 and begin mission extension services in mid-2020. The production of the second MEV is part of Orbital ATK’s longer-range plan to establish a fleet of in-orbit servicing vehicles that can address diverse space logistics needs including repair, assembly, refueling and in-space transportation.
“Work on MEV-1 is progressing rapidly toward a late 2018 launch with system-level testing beginning this spring,” said Tom Wilson, President of Orbital ATK’s Space Logistics, LLC subsidiary. “With the launch of MEV-2, Orbital ATK will continue to pioneer in-space satellite servicing for commercial operators. Intelsat’s commitment to a second MEV demonstrates not only the market demand for our servicing vehicles, but also the customer’s confidence in our product.”
Through its Space Logistics subsidiary, Orbital ATK will introduce in-orbit commercial satellite servicing with MEV-1 late this year. The MEV is based on the company’s GEOStarTM spacecraft platform, and controlled by the company’s satellite operations team. The MEV uses a reliable, low-risk docking system that attaches to existing features on a customer’s satellite, and provides life-extending services by taking over the orbit maintenance and attitude control functions of the client’s spacecraft. Each MEV vehicle has a 15 year design life with the ability to perform numerous dockings and repositionings during its life span.
“Intelsat was an early proponent of the potential for mission extension technology,” said Ken Lee, Intelsat’s Senior Vice President, Space Systems. “In-orbit life extension, such as that provided by our two contracts with Orbital ATK, provides additional flexibility to our fleet management, allowing us to direct capital to new satellites while continuing to generate economic value from satellites in orbit. We look forward to our continued collaboration with Orbital ATK on commercializing this important new service.”
The work performed on MEV-2 will span multiple locations across the company. Orbital ATK’s spacecraft components division will be responsible for manufacturing the structures, propellant tanks and solar arrays at the company’s locations in San Diego and Goleta, California. The Rendezvous, Proximity Operations and Docking (RPOD) laboratory, located at the company’s headquarters in Dulles, Virginia, will test the sensors, actuators and control algorithms that allow the MEV to approach and dock with the client spacecraft.
Orbital ATK plans to expand its satellite servicing capabilities to address additional in-orbit needs of customers. The company is investing significant internal capital and, through a NASA Space Act Agreement, working with U.S. government agencies to develop and implement new capabilities for the MEV fleet. These include next-generation life extension and repair vehicles, in-orbit assembly of large space structures and cargo delivery and related services to deep space gateways, such as in lunar orbit.
(from prior thread:)I would like to nominate the Mission Extension Vehicle as a potential non-CRS mission.It's a GTO/GSO launch, as many of its lucrative sats are, which fly mostly on F9, so it would likely not fly on Antares, for same.
MEV-1 already has a paying customer in GSO, SES IIRC, and is scheduled for a Q4 Proton launch. I expect future GSO missions will also use an LV that can send MEV to at least GTO.
Antares only has the oomph to push MEV to LEO. Since I don't have many MEV specs, what follows is complete speculation. Potentially an MEV variant can replace Cygnus's primary propulsion as a reusable, space-based, final stage. The theoretical gain is a cheaper Cygnus with more cargo capacity. Another possibility would be expanding the range of orbits accessible to cubesats travelling via ISS. An MEV could potentially chase down an astronaut drifting away from ISS.
Cygnus VV for the ISS is qualified to work in the KOS.
What allows the MEV to function is a large solar array from the long lived electric propulsion. The vehicle can be maneuvered to avoid antenna's and panels on a comsat.
But on the ISS this might not be such a good idea for prox ops. The array needed is too large.
Use as a reusable bus for handoff of a passive payload is something Lockheed's CRS-2 proposal also had (as well as a similar scheme reusing Soyuz (possibly also Progress), which has excess props on the vehicle for an earlier proposal). This wasn't appealing because of the need in the the CONOPs for multiple vehicle rendezvous/docking to deliver supplies, as opposed to the single dock/undock to complete the mission, thus too high of a risk to complete the mission (what NASA said).
Also, the need for propulsion for Cygnus is different than MEV. Enhanced is about 12,000lbs, about 3x more than MEV can handle. And the point of MEV is for station keeping, not to phase/deorbit a cargo container, which requires considerably more thrust for a shorter time (has to enter/clear the KOS in a relatively short time).
Here's where you could use a 10x scaled up MEV - you could use it to gradually move a Cygnus sized payload back and forth between low earth orbit and cislunar destinations. However, this would require a larger LV than Antares to launch it.
I expect that there already is a thread somewhere. I'm just the noob who hasn't figured out how to quickly find it. Directions to the forum thread about how to best search the forum are appreciated.
What is KOV?
My intent was to provide three general mission profiles using MEV for LEO space tug operations proof of concept tests. This could lead to the 10x scaled up MEV.
MEV shouldn't have many issues pushing Cygnus around once in orbit. I can accept that it would take far too long to go from the parking orbit Antares leaves Cygnus in to the ISS to be worth the effort. ≈
At the same point, as long as MEV can overcome drag, Cygnus could get to ISS eventually, given sufficient propellant reserves. For future reference, what term should I use instead of MEV variant to indicate that I believe MEV-1 is not up to the job but a mission specific version could work?
I'll look back through Lockheed's CRS-2 proposals. Thanks for giving me a direction to search. Multiple vehicle rendezvous/docking to deliver supplies is featured in most deep space plans so I currently think it should be a no-brainer not to develop operating procedures using existing LEO infrastructures. Learning why counter-intuitive decisions were made is why I am here.
Also, the need for propulsion for Cygnus is different than MEV. Enhanced is about 12,000lbs, about 3x more than MEV can handle. And the point of MEV is for station keeping, not to phase/deorbit a cargo container, which requires considerably more thrust for a shorter time (has to enter/clear the KOS in a relatively short time).
It's KOS. "Keep Out Sphere". Region of controlled space around the ISS that VV (Visiting Vehicles) have to be qualified to operate within.
Perhaps.
Unfortunately that's not how Orbital does things. And its been a hard sell to do one of these for Orbital and MDA. They would need a better business case to do so - that’s been the rub with something like that.
Tugs have been an ongoing thing for 20-30 years. Both in America and Russia.
The problem is when you've never had one operating before, it always seems too risky to "forward depend" on one to take the place of consecutive missions.
So likely the scenario has to be for a tug to coexist (not be mission ciritical, but an option), for a while to become relied upon for enough missions to allow such consideration (and possibly have another as a backup in orbit). These also make the business case expensive.
Also, the need for propulsion for Cygnus is different than MEV. Enhanced is about 12,000lbs, about 3x more than MEV can handle. And the point of MEV is for station keeping, not to phase/deorbit a cargo container, which requires considerably more thrust for a shorter time (has to enter/clear the KOS in a relatively short time).
Could higher-thrust lower ISP electric engines (or the same engines in a high-thrust mode) be used for rendezvous and docking operations?
ISP should still be well higher than chemical engines (though for such a short portion of the mission, ISP during these high-thrust phases would be less significant), elimination of redundant tanks reduces dry mass and improves reliability. Biggest gain would be the reduction to a single propellant instead of 2-3, greatly simplifying refueling.
Granted, the electricity requirements would be huge, but again, if they only have to be used during terminal rendezvous and only in short bursts (a few seconds at a time?) it might be feasible to store power in batteries first. High-thrust SEP has been demonstrated in the range of a couple newtons, which is at least within an order of magnitude of the sorts of chemical RCS in use now for docking operations (Cygnus RCS is ~31 newtons).
I'd be interested if anyones seen any studies on SEP-propulsion rendezvous viability/techniques
It's KOS. "Keep Out Sphere". Region of controlled space around the ISS that VV (Visiting Vehicles) have to be qualified to operate within.
Part of the mission profile would be to develop qualifications procedures for SEP spacecraft. LEO testing could be done without ISS, say using Cygnus after ISS departure. Using ISS opens more use cases though.
QuotePerhaps.
Unfortunately that's not how Orbital does things. And its been a hard sell to do one of these for Orbital and MDA. They would need a better business case to do so - that’s been the rub with something like that.
The business case is GSO satellite orders are down and MEV is based on the GEOStar-3 bus. Finding more uses for MEV keeps the production line running. I fully expect Orbital wants NASA to pay for two though.
QuoteTugs have been an ongoing thing for 20-30 years. Both in America and Russia.
The problem is when you've never had one operating before, it always seems too risky to "forward depend" on one to take the place of consecutive missions.
So likely the scenario has to be for a tug to coexist (not be mission ciritical, but an option), for a while to become relied upon for enough missions to allow such consideration (and possibly have another as a backup in orbit). These also make the business case expensive.
If Orbital is willing to be reasonable on the price we have the tool to develop procedures so we can rely on tugs at an affordable price. One of the things I'm hoping to find out is if that reasonable price can be held under three Soyuz seats.
It isn't/wasn't an issue as to price. It is an operational issue. Until the operational issue is dealt with, no proposal would likely get any budget, any interest at all. As I'm attempting to communicate.
This is why its difficult for people to understand why something doesn't go further, even if it might be an interesting idea.
It isn't/wasn't an issue as to price. It is an operational issue. Until the operational issue is dealt with, no proposal would likely get any budget, any interest at all. As I'm attempting to communicate.
This is why its difficult for people to understand why something doesn't go further, even if it might be an interesting idea.
So how do the operational issues get resolved without flying some hardware to test solutions?