Possibilities for a single launch architecture of the Artemis missions, Page 2: using the Boeing Exploration Upper Stage.

 Copyright 2023 Robert Clark

  A comparison between the Apollo and Orion capsules:

 Rarely has a design mistake been so clearly illuminated by a single picture. Note the Orion capsule is nearly double the size of the Apollo capsule in mass. But rather than making Orion’s Service Module twice as big as the Apollo Service Module, as it should be to get similar performance, instead it is smaller by 1/3rd.

 Orion’s service module is based on ESA’s ATV cargo tug to the ISS, which had a 4.5 meter diameter and a 10 ton propellant load.

BUT THERE WAS NO REASON TO KEEP IT AT THAT SAME DIAMETER FOR THE ORION USE, NOR TO KEEP THE SAME SIZE PROPELLANT LOAD.

 If instead the diameter was made to match the capsule’s diameter, as was the case with Apollo, there would be an additional 20 cubic meters of volume inside the Service Module, well more than enough to hold an additional 10 tons of the storable propellant used.

And that is all that is needed to solve THE major problem of the SLS/Orion approach: the fact it can’t send the Orion and a lunar lander to low lunar orbit, and bring the Orion back to Earth again.

 It is because of that the idea of the lunar Gateway was proposed, where the SLS would only have to take the Orion to a further out orbit.

 But if instead the Service Module was given that additional 10 tons of propellant then it could send both the Orion and a ca. 15 ton lunar lander to low lunar orbit, and have enough propellant left over to bring the Orion back to Earth, a la the Apollo architecture.

 Rarely, has a mistake been so clearly exposed, especially when its solution is so clearly made apparent as well.

 In the blog posts, "ESA Needs to Save NASA's Moon Plans", and "Possibilities for a single launch architecture of the Artemis missions", I wrote about getting a single launch format for the Artemis lunar lander missions by using the Ariane 5 as an upper stage or by using two Centaur V stages as the upper stage for the SLS, respectively.

 This stemmed from dislike of the plan NASA was endorsing of using multiple flights and refuelings of the SpaceX Starship as the lander. I also objected to the high cost projected for the planned Boeing Exploration Upper Stage(EUS), being nearly half the cost of the entire SLS per flight, nearly $1 billion.

 However, NASA has negotiated a better price structure for the EUS. And it appears NASA is wedded to the Boeing EUS. Then I'll discuss a single launch architecture using the Boeing EUS upper stage.

 The payload to LEO of this version of the SLS with the Boeing EUS, which is version Block 1B, will be 105 tons to LEO. The current fueled mass of the Orion+Service Module is 26.5 tons. An additional 10 tons of propellant will bring it to 36.5 tons. 

 In the blog post, "A low cost, lightweight lunar lander", I discussed a lunar lander at a 13-ton total fueled mass based on the Cygnus capsule given life support as the crew module, and the Ariane 5 EPS storable propellant stage as the propulsive stage for the lander.

Calculations for the delta-v to the Moon and back.

 The Orion with its fully fueled service module has a mass of 26.5 tons. The propellant load of the service module is ~10 tons, with 16.5 total tons dry mass of the Orion and service module. We'll add an additional 10 tons propellant to the service module to bring the total mass to 36.5 tons, including 20 tons of propellant.

 The AJ-10 engine used has a vacuum ISP of 319s. We'll assume a fueled lunar lander of size ~13 tons, as described in the blog post, "A low cost, lightweight lunar lander", comparable in size to the Apollo missions lunar lander. So, a 16.5 + 13 = 29.5 ton mass for the vehicles that need to be put in low lunar orbit. But remember also we need to have some propellant left over in the service module to bring the Orion back home to Earth.

 For the delta-v calculation, after the SLS places the Orion/Service Module/lunar lander stack in trans-lunar injection(TLI) towards the Moon, we need 0.9 km/s to put the stack into low lunar orbit. This requires 13 tons of propellant, leaving 7 tons remaining:

319*9.81Ln(1 + 13/(29.5 +7)) = 0.950 km/s. The lunar lander will then be launched to land on the Moon while the Orion and service module remain in lunar orbit.

 After the lander mission is completed, the lander returns the astronauts to the Orion in lunar orbit, and the lander is then jettisoned. The Orion's service module is then fired to bring the Orion back to Earth. After lander jettison, the dry mass of the Orion and service module will be 16.5 tons. Then the 7 tons of remaining propellant is sufficient to perform the trans-Earth injection(TEI) burn of 900 m/s to escape lunar orbit and place the spacecraft back onto the free return trajectory back to Earth:

319*9.81Ln(1 + 7/16.5) = 1,100 m/s. 

 So the total mass that needs to be sent to trans lunar injection(TLI) on a path to encounter the Moon is 36.5 + 13 = 49.5 tons. Now use the rule-of-thumb that a Centaur-like hydrolox stage can send to TLI at a 3,000 m/s required delta-v a payload mass equal to its propellant load.

 So use for a third stage atop the Boeing EUS the Centaur V at an 50 ton propellant load and 5 ton dry mass. This then results in a total mass to LEO of 104.5 tons consisting of the 55 tons of the Centaur V plus the 49.5 tons of the Orion capsule/Service Module/lunar lander, within the lift capacity of the SLS Block 1B to LEO.

  Robert Clark

Ariane 5 Core plus 4 Ariane 4 side-boosters as a manned launcher, page 2: use as another ISS supply vehicle.

Copyright 2015 Robert Clark

  In the blog post "Ariane 5 Core plus 4 Ariane 4 side-boosters as a manned launcher", I suggested such a configuration would give a quicker, cheaper implementation of the Ariane 6 that would have the advantage that it could also be used as a manned launcher. 

Ariane 5 Core plus Ariane 4 side boosters added

 A recent news report gives this even greater importance, the fact that France wants to sell its stake in Arianespace to Airbus Safran:

French Divestment Will Put Arianespace in Airbus Safran’s Hands.
by Peter B. de Selding — June 10, 2015
http://spacenews.com/french-divestment-will-put-arianespace-in-airbus-safrans-hands/

 This is good news for the commercial space approach to lowering launch costs. For instance, the use of solid rocket side boosters on the Ariane 6 helps to subsidize the French military's use of solid rocket missiles. Without the French government owning a part of the company, you are freer to choose the most cost-effective approach instead.

GEO satellite launcher.
 The calculation for this configuration without an upper stage was for 15 metric tons(mT) to LEO. Much of the satellite launch market however is to geosynchronous orbit. Using an existing upper stage for this version would eliminate another development cost for the current version of the Ariane 6 which envisions a new large upper stage using the new Vinci engine.

 For this configuration use instead the already developed Ariane H10-3 upper stage. This has a 1,570 kg dry mass, 10,470 kg propellant mass, 62.7 kN vacuum thrust and 446 s vacuum Isp. Plug these numbers in for the upper stage into Schilling's launch performance calculator with the same numbers for the Ariane 5 core and Ariane 4 liquid-fueled side-boosters as used in the "Ariane 5 Core plus 4 Ariane 4 side-boosters as a manned launcher" post.

 For GEO satellites the launchers actually send the satellites to geosynchronous transfer orbit (GTO) which is a highly elliptical orbit that reaches from LEO to GEO, with the satellites onboard propellant and engines providing the final kick to a circular orbit at GEO. For the GTO orbit, enter in Schillings calculator the default perigee of 185 km, 35,000 km for the apogee, and an inclination of 5.2 degrees to match the latitude of the Ariane launch site. Then the calculator gives the results:

Mission Performance:

Launch Vehicle:	User-Defined Launch Vehicle
Launch Site:	Guiana Space Center (Kourou)
Destination Orbit:	35000 x 185 km, 5 deg
Estimated Payload:	7948 kg
95% Confidence Interval:	6380 - 9952 kg

"Payload" refers to complete payload system weight, including any necessary payload attachment fittings or multiple payload adapters
This is an estimate based on the best publicly-available engineering and performance data, and should not be used for detailed mission planning. Operational constraints may reduce performance or preclude this mission.


Lowered development costs reduces launch pricing. 
 Replacing the solids with the liquid-fueled boosters that had already been used on the Ariane 4 would eliminate the development costs of having to develop the new solids now planned for the Ariane 6. Since the need to recoup development costs amounts to a significant proportion of the launch price of rockets, the minimal additional development costs would make it much easier for this version of the Ariane 6 to meets its low launch cost goals. And in addition to the much lowered development costs, the minimal additional development would lead to a rapid route to its deployment.

 Also, ESA is considering some versions of the reusability in returning the engine compartment of the core stage. However, by using liquid side boosters you can make the side boosters reusable as well by doing a vertical landing on those.

 Inexplicably, in ESA trade analyses of liquid-fueled versions for the Ariane 6 versus solid booster versions, no consideration was given to the major advantage of liquid fueled versions of providing Europe with an independent manned launch capability. Note this all liquid implementation would give a manned vehicle using four liquid-fueled boosters attached to the core stage, as both the
Russians and the Chinese have done to produce their manned launchers. And because of the rapid development time due to the minimal new development needed, Europe could probably field this manned launcher by the time the Americans field theirs, expected in 2017.

Use as an ISS supply vehicle.
 Last months failure of the Falcon 9 launch to resupply the ISS reveals another reason such fast development time is important. All three of the current ISS cargo launchers have experienced recent launch failures. Then another launcher to serve as a cargo supply vehicle would be useful. Because it would have a short development time and low development cost, this version could serve as valid alternative to the other launchers. Then this opens up another revenue source for this all-liquid version of the Ariane 6.

 Moreover, the Cygnus capsule, being European, could also be used as a low cost cargo capsule, rather than the expensive ATV.

Cygnus module.

     Bob Clark

On the lasting importance of the SpaceX accomplishment, Page 5: a letter to the European space industry.

	Copyright 2013 Robert Clark
	Subject : A low cost, all European, manned launcher. Date :     Sun, Jun 16, 2013 07:37 AM EDT From :     "Robert Clark" <****@****> To :     ****@****

 This article discusses the possibility of using the ATV as a manned spacecraft:

Shifting Constellations: Europe Eyes China in Space Race.
By Kevin Holden Platt in Beijing February 08, 2013 – 03:17 PM
http://www.spiegel.de/international/europe/esa-mulls-new-alliance-as-china-becomes-space-leader-a-882212.html

 Russia and China have their own manned spaceflight program, as will the U.S. once again soon. Even India and Japan are planning their own manned spaceflight programs. The European Union has been the greatest economic power in the world or a close second to the U.S. over the last few years. European space advocates then should regard it as unacceptable that Europe has no plans to develop a manned spaceflight capability.

 The main impediment has been cost. But such costs would be reduced greatly if the focus was on small rather than large. The ATV is a large, expensive spacecraft as is the Ariane 5. But there is no need to have a spacecraft as large as the ATV simply to carry a crew, or a rocket as large as the Ariane 5 to launch them to orbit. My recommendation is instead to adapt, for example, the much smaller Cygnus, designed and built in Italy, for the purpose.

 This would allow a much smaller vehicle of Ariane 6 size to be used as the launcher. The complaint that the Cygnus does not have life support or a heat shield is not valid since that would have to be provided to the ATV as well. Another possibility for the capsule would be the 'Magic Dragon' capsule developed by Elson Space:

PICTURE: UK built SpaceX capsule revealed.
By: ROB COPPINGER LONDON 11:25 15 Apr 2008
http://www.flightglobal.com/news/articles/picture-uk-built-spacex-capsule-revealed-222995/

 For this to be the case, you would have to adopt the liquid-fueled version for the Ariane 6, eventhough the solid-fueled version has been decided upon. The Academy of Air & Space in France has criticized the choice of the solid-fueled version on the grounds that it does not advance the technology and has limited flexibility:

Academy Urges Europe To Halt Work on ‘Wrong Choice’ Ariane 6 Design.
By Peter B. de Selding | May. 30, 2013
http://www.spacenews.com/article/launch-report/35546academy-urges-europe-to-halt-work-on-‘wrong-choice’-ariane-6-design#.Ubqa4cu9KSO

 But another key advantage was not mentioned by the Academy, that the liquid-fueled version could serve as a manned launcher. To me this is an overwhelmingly important fact that needs to be mentioned in regards to their relative merits. This would be a profoundly important advance in European technology. Look at how the Chinese space program was regarded as having been advanced by developing its manned spaceflight program.

 Because of this advance, to some the Chinese space program is regarded as having surpassed both the European and American ones. I am aware of the fact that the choice of the solid-fueled Ariane 6 was largely political, shaped by the requirements of geographical return which the ESA has to follow. However, I am a strong proponent of the commercial space approach to launcher/spacecraft development. To me it is an extremely important fact that the costs to the government were reduced by 90%(!) by both SpaceX and Orbital Sciences in developing their respective launchers.

 For a commercial enterprise in the business world, if you found a way to reduce your costs by 90% that would be a development that would be hailed for decades as an extremely important advance. But because space programs are government run this is something that still is only spoken of in hushed tones by NASA.

 Still nevertheless NASA's commercial space program was a tremendous success in producing launchers at greatly reduced costs to the government. Note that NASA was forced to this because of the high cost of producing manned launchers under normal governmental financing procedures. This success then should be modeled by European space agencies in producing manned launchers even if it requires bypassing the ESA, with its geographical return requirements.

 Here I discuss how the liquid-fueled Ariane 6 could serve as a manned spaceflight vehicle:

On the lasting importance of the SpaceX accomplishment, Page 4: how the Ariane 6 can beat both SpaceX and the Russians.
http://exoscientist.blogspot.com/2013/06/on-lasting-importance-of-spacex.html


   Bob Clark