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About jinnantonix

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    Sr. Spacecraft Engineer

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  1. ACES has the rights specs. But ULA is busy getting the Vulcan ready, and doesn't appear to be interested in bidding for any of the contracts.
  2. I think you have nailed the constraints for Artemis perfectly. In many of the speculations around best HLS design, it has been pointed out that the most efficient design is a 3-stage lander using a transit vehicle for the first stage to get from NRHO to LLO. Much talk of re-usability, nuclear engines, etc for this transit stage. However beefing this up so it can act as a general purpose tug for various LEO to cislunar operations, and going cryogenic and expendable, makes sense. Being able to use this to craft to deliver payloads directly to the lunar surface would be an alternative to the lander carrying payloads, and allows the SLS/Orion/HLS design to focus on just humans (and all it's safety overheads). So a potential high level mission design for Artemis 3 could be: (1) Commercial carrier launches tug and static payload direct to lunar surface. Includes rover, science instruments, emergency habitation etc. (2) Commercial carrier launches tug + HLS (lander ascent and descent vehicle) to NHRO or lowly elliptical staging point (3) SLS/Orion delivers humans for LOR at staging point, shortly after HLS system arrival. Humans transfer to lander, and tug delivers lander to LLO or suborbital path to lunar surface landing site, tug expended Expendable HLS descent vehicle carries the humans to the lunar surface After surface operation HLS ascent vehicle has sufficient dV to return directly to the stage point. Re-usable AV? Transfer to Orion and return to Earth. So, one SLS launch and two large commercial launches, with one LOR and no fuel transfer required to complete the mission. If the AV is reusable, launch 2 would carry fuel + pumping facilities and provisions instead of the AV.
  3. I am sure the teams putting together the HLS bids are well aware of that. My video above simulates a 3-stage craft with a 2.7t ascent vehicle and 1 ton surface payload delivery (including humans and life support). The ascent vehicle is reusable provided it can be refueled at the Gateway. Perhaps this is adequate to achieve the Artemis mission goals?
  4. Excellent graphic, with a lot of really interesting information. I tried to follow your "napkin maths", but with difficulty. The basic points I get are: LLO is ideal for optimising the lander for delivery of payload to lunar surface. Basically you can get a better lander and more payload to surface per mission. NRHO or Lagrange Point is ideal if building a space station, and LLO or ELO is not ideal. Lowly ELO is better than highly ELO is better than LLO. For delta-v, lowly ELO is better than NRO, Lagrange, and highly ELO. Good point in favour of the Gateway. From your points above, it does make sense that if there is a space-station, NRHO or Lagrange is the best location for station-keeping. So, two options emerge if Gateway happens, then the Artemis plan for NRHO is OK as it provides best station-keeping, though places stress on the lander design **, and reduces payload to surface. if no Gateway ++ then: Modify Orion to allow it to go to lowly ELO, as this gives best compromise between station-keeping and payload to surface Scrap Orion and start again with an Apollo style capsule, and potentially single launch to lowly ELO. Notes: ** if the current tender for HLS fails to come up with an adequate facility for humans and payload delivery, it may yet spell doom for the Artemis architecture, and Gateway. ++There is probably no option for lander re-usability in the "no Gateway" option. There is no question that FH could be man-rated, the same for New Glenn, but it would result in a delay of at least a decade. And if we were going to do that, then we would likely scrap Orion in it's current form and rebuild that with a LLO capability, and also scrap SLS altogether in favour of FH and NG. So $Billions in development costs wasted, and throw a lot of people out of work, probably lose a lot of skills and experience. What staff remain will likely be tax-payer funded to achieve the man-rating on the commercial carrier. This would kill the current inertia toward a moon landing this decade, with no certainty it would start up again. Not sure why anyone would want that. My vision (and I am sure I am not alone) is that FH and NG will eventually be man-rated and will be the primary carriers of humans and equipment to space by 2030 and beyond. The R&D for this can and will be carried by the commercial carriers, not the taxpayer. If we want anything to happen this decade, we need SLS and Orion. The only question is whether we go ahead with Artemis and Gateway, or redesign for Apollo style single non-re-usable missions.
  5. The SLS is designed to launch Orion, and it is by far the closest to achieving human rating. The fact is, Orion is a big craft, with room for 6 astronauts, much bigger and heavier than the Apollo return capsules. The intent is to have a craft more versatile for multiple BLEO operations (cislunar, heliocentric and Mars), and ability to return directly from heliocentric orbit to the Earths surface (ie survive >3km/s re-entry speeds). The downside of this is that it is just too big to get to LLO and return to Earth in a single launch with current rockets. A bigger human rated rocket is a decade away at least. I don't understand the obsession with getting Orion to LLO. Why is it necessary? Why not make it standard practice for Orion to enter a highly elliptical orbit, and lunar operations must then be capable of getting to and from the lunar surface from that point? I simply do not see the downside of that, and creating complex a difficult scenarios to achieve Orion LLO are only going to add cost and time. A better question: "Is the Gateway needed?". I would argue, no. There is no reason why each mission could be completed with an ad hoc LOR in highly elliptical orbit. But having a staging point for cargo delivery and a permanent position for advanced comms has some advantages. Here is my RSS simulation of Artemis 3 which assumes LOP-G is in place, and completes a manned lunar landing with two launches (SLS + FHe). I think this is basically what NASA is aiming at. My 3-stage lunar lander meets the spec for HLS, but may be too small in physical dimensions to support 2 astronauts on the surface for 2 weeks. The current HLS proposals seem to be too large and heavy to complete the mission from a single FHe launch. The options are single SLS Cargo launch (bad idea, way too expensive) or better two commercial Falcon Heavy launches with EOR.
  6. @JacobJHC I have noticed there is no entry for "low cost", and thinking of giving it a try. Are there any rules regarding re-usability, e.g. subtracting recovered costs of the returning craft at the KSC, or is it just the cost of the craft (or crafts) at launch from KSC (no recovery)?
  7. Without seeing your design, it is difficult to be sure. Can you move your rapier engine boosters so that they are aligned with the centre of mass of the craft? So when you eject them the CoM of the craft remains unchanged.
  8. @Jestersage , further to @tater 's comment, Artemis proposes that the Lunar Gateway (LOP-G) will be in Near-Rectilinear Halo Orbit, which is roughly equivalent to an elliptical polar orbit with Pe=2,000km over the north pole and Ap=60,000km over the south pole. Any en route craft (Orion or Lander) would do a TLI adjusted to pass close over the lunar north pole and dock with the LOP-G when it is about midway to Pe. The lunar lander undocks, decelerates to LLO, descends and ascends, then rendezvous and docks with the LOP-G. The crew then transfer to the Orion to return to Earth.
  9. Sounds like a project manager's nightmare. I have seen this happen, where the delivery folk are incentivised to delay, or to sabotage presales activities, so they can sit on their hands and still get paid. Not saying it is the case here, but it does happen.
  10. Boeing doesn't get paid until they deliver against the milestone. Yet they will have fixed outgoings for their permanent staff, and requirements for fixed outcomes against their contractors. So there is actually an incentive to deliver against a timeline, they need to reach the milestone or they run out of cash.
  11. This will require additional avionics, a very complex remote control services (via the LOP-G?), more mass to orbit for lander legs and fuel - all for "possible salvage potential"? I think the plan for reuse needs to be very well established to make this a viable strategy. To resolve the problem of ejecta, attach stretchy, light weight, heat resistant fabric/mesh between the lander legs. On leg deployment, the material forms a skirt from above the pads, to a few meters below. Each craft has it's own skirt.
  12. I understand why a crasher stage looks ugly, but what the difference between a crashed drop tank or two, and a descent stage sitting neatly on the surface? How much are we willing to compromise efficiency with aesthetics? I sense the idea of the Dynetics design is that the AV is re-usable, including legs. If that is the case, then it's either a big inefficient single stage craft, or drop tanks/crasher stage.
  13. Not if it is a single stage craft. The Lockheed Martin Mars-Precursor Lunar Lander single stage craft was a dud with respect to payload delivery. It could land humans, not much else. Even with capsule removed, it is very inefficient compared to a staged craft. The LH 2 stage concept , way way better. Utilising the the Orion pressure vessel and building the ascent vehicle from service module components (8x R-4D + AJ10-190)? Good idea I think. If the Dynetics design is 2 stage. i.e. includes a transit vehicle/ drop tank inline under the main body that is ejected prior to the AV landing, there is much greater payload potential, as well as much better potential for capsule/habitat re-usability. I like the idea of dropping the TV just prior to landing, advantages are the short ladder and re-usable leg mechanisms.
  14. It needs to have something more than what we see in this picture to even get from LLO to Surface and back. Something extra is needed. e.g. A transit vehicle or drop tanks. Obviously the lander needs to be able to rendezvous at the Gateway. The initial flight may be more direct (maybe), but NASA will not select a lander design that cannot do the Artemis mission profile including Orion rendezvous at the Gateway. My guess is that it will be launched by two Falcon Heavy LVs, EOR docking the lander shown (ascent vehicle), with a hypergolic fueled transit vehicle, autonomously guided rendezvous with the Gateway for crew transfer from the Orion. The transit vehicle then carries the lander to a suborbital path to the lunar landing site, and the TV is then dropped immediately prior to the AV landing on the lunar surface. The AV is potentially re-usable - with each mission a new Transit Vehicle docks at the Gateway, refilling the AV tanks. The engines are a mystery. Dynetics have previously partnered with Aerojet Rocketdyne. Eight fixed 490 N model R-4D-11 auxiliary thrusters would not have enough thrust. Perhaps the artist left out the main engine (e.g. AJ10-190). Alternatively Dynetics may break their AJ partnership and use SuperDRACOs, although eight engines is overkill, and compromises re-useability.