Rocketdoc Notes – Week of December 6, 2020
Will the Artemis Program land the first woman on the moon by 2024?
The Artemis program is a U.S. government-funded human spaceflight program that has the goal of landing "the first woman and the next man" on the Moon, specifically at the lunar south region by 2024. The program is carried out predominantly by the NASA, U.S. commercial spaceflight companies contracted by NASA, and international partners including the European Space Agency (ESA), the Japanese Aerospace Exploration Company, the Canadian Space Agency (CSA), the Italian Space Agency (ASI) the Australian Space Agency (ASA), the UK Space Agency (UKSA) and the United Arab Emirates Space Agency (UAESA). NASA is leading the program but expects international partnerships to play a key role in advancing Artemis as the next step towards the long-term goal of establishing a sustainable presence on the Moon, laying the foundation for private companies to build a lunar economy, and eventually sending humans to Mars. Building an international coalition to conduct this program shows that the adults were in charge this time because that makes it unlikely the Biden government will cancel the Artemis program, like the Obama government did its predecessor with the same goals, the Constellation Program, back in 2010.
The program was initiated in December 2017 when President Donald Trump signed space Policy Directive 1, authorizing the lunar campaign. The 2017 version of Artemis draws upon ongoing spacecraft programs including Orion, the Lunar Gateway, and the Commercial Lunar Payload Services Program (CLPS); and adds a yet-to-be-developed crewed lander. The Space Launch System (SLS) was to serve as the primary launch vehicle for Orion, while commercial launch vehicles are planned for use to launch various other elements of the campaign. NASA requested US$1.6 billion in additional funding for Artemis for fiscal year 2020, while the Senate Appropriations Committee requested from NASA a five-year budget profile which was needed for evaluation and approval by the Congress.
Commercial Lunar Payload Services Program
Fast forward to late 2020 and we see the program is advancing well despite not yet getting the full asked for funds from Congress. For instance, the Commercial Lunar Payload Services Program has been funded and is on-Schedule and the first payloads will be launch mid-year 2021 as shown if figure 1 below. This is an excellent way to scope out the resources and conditions to be found at future sites for crewed landings. Also, since they are already in hardware development, there is little likelihood that these commercial missions would be cancelled by the incoming Biden administration. It is likely that not all of these missions will be successful, but with multiple missions carrying multiple sensors to multiple areas of interest, they should be a good investment.
Figure 1 – Planned Commercial Lunar Payload Services Missions
Orion Crewed Spacecraft
Orion is a class of partially reusable space capsules to be used in NASA’s human spaceflight programs. The spacecraft consists of a Crew Module (CM) manufactured by Lockheed Martin and the European Service Module (ESM) manufactured by Airbus Defense and Space AD&S). Orion is capable of supporting a crew of six beyond LEO and can last up to 21 days undocked and up to six months docked. It is equipped with solar panels, an automated docking system,and a state-of-the-art glass cockpit. A single AJ-10 hypergolic-fueled rocket engine provides the spacecraft's primary propulsion. Although compatible with other launch systems, Orion was initially designed to launch atop a Space Launch System (SLS) rocket, which is why it uses a tower launch escape system (necessary to escape from a solid rocket motor failure).
The Orion Multi-Purpose Crew Vehicle (MPCV) was announced by NASA on May 24, 2011. Its design is based on the Crew Exploration Vehicle (CEV) design from the cancelled Constellation program, which had been awarded to Lockheed Martin under a 2006 NASA contract. The command module is being built by Lockheed Martin at the NASA Michoud Assembly Facility while the Orion Service Module is being built by Airbus Defense and Space with funding from the ESA.
By May 2020, the ESA had signed an agreements with NASA to provide three service modules for Artemis as part of its barter arrangement with NASA to be a member of the Artemis program. The ESMs cost approximately €250 million each to acquire from AD&S, not counting the costs incurred by the ESA directly. The third ESM is slated to fly in 2024. If you have been reading the news lately you will know a major schedule slide in launch dates is apparent. Currently the Orion program is over-cost, overweight, hard to service, and late. We will see if those problems can be fixed in time. It is an essential part of the Artemis Program.
The lunar gateway has been an optional part of the human lunar program since the Constellation Program back in 2005 (I had NASA contracts in 2006 designing landers with and without a lunar Gateway at the L1 Lagrange point (roughly 60,000 miles above the moon between the Earth and the Moon). The L1 Gateway location is semi-stable, but easy to maintain. It has one saving grace, it is accessible quickly from any place on the lunar surface. The currently proposed Lunar Gateway is in a polar near-rectilinear halo orbit (NRHO) with a perilune at 3000 km and an apolune at 70,000 km. The NRHO is in a halo orbit because the interaction between the Earth and Moon’s gravities cause it to rotate in approximate lock with the moon’s rotation so it always looks like a halo around the moon to observers on Earth. That means the gateway is very accessible from the Lunar South Pole with a launch window every seven days when the Gateway passes over the south pole lunar launch site but pretty useless for missions to any other parts of the moon not in the ground track of the fixed halo orbit. The NRHO was a good solution if NASA is only going to build one base at a Lunar pole.
Back in 2005 we used the L1 Gateway to store fuel and reusable stores (e.g., EVA suits) for future lunar missions so they didn’t have to be taken back to earth between missions. It also provided a safe haven in case a mission had to escape from the surface suddenly. The Gateway in NRHO doesn’t meet these requirement because it was originally planned for a deep space station to study the moon and measure deep space radiation effects on animals. As you can tell NASA is currently keeping its options alive in case project Artemis is cancelled by the Biden administration and then they will go back to a lunar observation role. If the Artemis program manages to stay alive, I expect the Lunar Gateway to either go away or migrate to L1 where it is applicable to bases anywhere on the Lunar surface.
It is much more efficient to support Lunar activities using Low Lunar Orbit (LLO) rendezvous just like Apollo. This is especially true if nothing is left in LLO after payload transfer to or from the orbit transfer vehicle (OTV). For Apollo the landings were relatively short and timed such that the later orbit ground track crossed over the landing site. For future lunar bases nothing is left in orbit as the OTV returns to Earth after transferring payloads to the Lunar-Based Lander. This LLO rendezvous system minimizes the payload mass to LEO for every kilogram of payload mass to the moon (this ratio of mass delivered to LEO over the mass delivered to the lunar surface is sometimes referred to as “gear ratio”).
As it happens, NASA is thoroughly locked into the NRHO Gateway right now. This is because the existing Orion crew transportation system has a total DV capability of 1338 m/s, while an Apollo-like trip from Translunar Injection (TLI) in and out of LLO to transfer crew to the lander takes a DV of roughly 1650 m/s. Therefore, Orion is unable to perform crew transfers to the Lunar Lander unless it harnessed itself to the Gateway. With the Gateway at NRHO, the Orion system only needs 420 m/s to enter lunar orbit and rendezvous, and same 420 m/s to depart the Gateway and boost into the transfer orbit back to Earth. This provides NASA with additional Orion payload capability for future mission growth.
However, with the lunar lander based at the NRHO Gateway, the lander trip from the Gateway to polar LLO would require a DV of 730 m/s and half a day. This significantly impacts the lander design since its landing total DV has been increased from 2135 m/s to 2865 m/s, and the ascent total DV from 1860 m/s to 2590 m/s. Based on my old NASA lunar lander design models, if we sized the lunar transportation system to deliver 15 mT to the lunar surface, the total lander mass at departure from the Gateway would be 60.4 mT and the total lander mass if it was fueled in LLO would be 39.8 mT. This is a significant increase in Lander mass and has implications throughout the transportation chain. Assuming new reusable upper stage to deliver payload and propellants from LEO to a transfer point near the moon, and a reusable lunar lander that is refueled at that same transfer point, the total mass that has to be delivered to LEO to deliver the 15 mT to the surface, is 199.3 mT if we’re using the NRHO Gateway as our transfer point to deliver propellants and payload, and 103.35 mT if we use LLO as the transfer point. The payload mass to LEO for the Falcon Heavy is 64 mT, for the SLS Bk1 95 mT, and for the SPLS Bk2 130 mT. Therefore, an efficient OTV plus Lander combination is not in the cards with existing launch systems so a three-part system like Apollo (Apollo w/ service module, lander, and ascent stage) with each element launched separately is the way to go. However, the three-part system is also complicated by the extra DVs caused by NRHO Gateway, which made sense for small lunar exploration and science missions but makes no sense for a major lunar base-building operation, and the economics suck.
Lunar Lander Concepts
In October 2019, it was announced that Blue Origin, Lockheed Martin, Northrup Grumman, and Draper Laboratory would collaborate to create a proposal for the Human Landing System (HLS) for NASA's Artemis program with Blue Origin serving as the primary contractor with a variation of its Blue Moon Lunar Lander serving as the descent stage. Lockheed Martin would build the ascent stage, in part based on its Orion crew capsule technology. Northrop Grumman would build an Orbital Transfer Stager (OTV) based on its Cygnus spacecraft technology. The lander was projected to launch on Blue Origin's reusable New Glenn rocket. In April 2020, Blue won a design contract of US$579 million from NASA to advance the design of a human-rated lunar lander for the Artemis program during a 10-month period in 2020–21. Blue's proposal team included Lockheed Martin, Northrup Grumman, and Draper Laboratory, each acting as a subcontractor to Blue who will provide the descent element and also be the integration lead. The proposed spacecraft consists of an in-space transfer element (OTV), a human-rated ascent element, plus the Blue-provided human-rated lander The NASA paid design work will start in 2020 and continue into 2021. The human-rated lander will be a variant of the Blue Moon lunar lander that Blue had been working on for nearly three years.. At the end of the ten-month program, NASA will evaluate which contractors will be offered contracts for initial demonstration missions and select firms for development and maturation of lunar lander systems. The so-called Blue Moon Lander mockup is shown with Jeff Bezos in Figure 1 below.
Blue Origin has recently successfully tested the 10,000 lbf BE-7 LOX/LH2 lander throttleable rocket engine. The integrated OTV with Lander and Ascent stage is shown in Figure 2 below. All of the elements shown have some previous development work.
Figure 1 – Blue Moon Lander Mockup
Figure 2 – Proposed Integrated Blue Team Spacecraft (OTV, Lander, and Ascent Stage with Crew Cab)
The second contender team for landing humans on the moon is Dynetics, working with Sierra Nevada Corporation’s Space Systems. This team participated in some early human landing system (HLS) design studies under NASA's HLS Appendix E program. They submitted a proposal to NASA for HLS Appendix H for a concept called the Dynetics Human Landing System (DHLS) which in April 2020, was one of three proposals funded for further design work in a US$253 million in NASA development funding contract during 2020/21. The Dynetics HLS concept after separation of drop tanks is shown in Figure 3 below.
Figure 3 – Dynetics Lander Configuration on the Moon after separation of drop tanks
The Dynetics Autonomous Logistics Platform for All-Moon Cargo Access (ALPACA) Lander concept relies on in-space refueling to be able to carry out its mission. That refueling will initially be done in LEO by additional launches carrying propellant that is transferred to the lander drop tanks in LEO. The lander and the tankers will be launched on a United Launch Alliance Vulcan Centaur rocket. For the initial 2024 landing mission the initial launch will be followed by two additional Vulcan launches carrying transfer propellants. Propellant from those rockets’ Centaur upper stages will be transferred to the lander. Most of that propellant will be carried in saddlebag-type drop tanks not shown in the figure above. Those tanks are discarded after the TLI burns and before LLO injection. As I understand the concept of operations the Orion system is launched on a separate rocket and rendezvous with the ALPACA lander in LLO or at the Gateway station and transfers crew and extra propellants. The ALPACA then leaves the Orion in orbit and preforms a round-trip visit to the lunar surface. When the ALPACA returns the crew transfers to Orion and heads back to Earth while the ALPACA remains on orbit for future refueling.
The biggest challenge with this approach is losses during cryogenic propellant transfer and “boiloff,” or loss of cryogenic propellants as tanks warm up. To address this, Dynetics plans to carry out the Vulcan Centaur launches on “14-to-20-day centers,” or roughly two to three weeks apart. Dynetics worked closely with NASA on the concept of operations, and the ULA plans to ensure that the operational scenario is viable and feasible. That would be a much faster launch rate than what ULA’s existing vehicles, the Atlas 5 and Delta 4, have traditionally supported. In-space refueling technology must be tested in space prior to a crewed flight of the lander. Dynetics has put together a plan that will demonstrate all of the critical functions of the lander. They plan to demonstrate in-orbit refueling of the lander they put any crew on the lander.
In the long term, propellant for the Dynetics lander could come from other sources. The lander could be a customer for future commercial propellant depots around the moon, or use propellant created from extracting water ice on the lunar surface. Having the ability to fill the ALPACA liquid oxygen tanks on the lunar surface could enable new mission classes, like hopping around to other parts of the moon to accomplish some key science objectives. Note, that this also holds true for the Blue Moon Lander.
The third contender for NASA’s HLS program is Space-X with their Starship HLS concept. They were awarded a US$135 million NASA contract. The Starship HLS concept is identical to the Starship lunar delivery system I covered in the October 18th Rocketdoc Notes. It relies on refueling the Starship in LEO using six launches of the Starship Tanker version. The advantage of the Space-X Starship concept is that it can theoretically deliver 100 mT to the lunar surface for about $850/ kg and return home empty. They have a huge development challenge ahead to reach their goal, but they are currently building and flying full-scale hardware.
At the end of the ten-month HLS program, NASA will evaluate which contractors will be offered contracts for initial demonstration missions and select firms for development and maturation of lunar lander systems. However, in July 2020 the House Appropriations Committee rejected the White House's requested funding increase. The bill proposed in the House dedicates only US$700 million towards the Human Landing System, US$3 billion short of the requested amount.This means that there is little chance the Blue Origin or Dynetics teams will get sufficient funding to complete their systems in time for a 2024 return to the moon. I suspect the Commercial Lunar Payload Services Program will go ahead on schedule and future NASA HLS funding will be delayed or cancelled. This is life in the Space Program.
The bottom line is that the first woman and next man on the moon will probably be Space-X or Blue Origin employees. This is because U.S. billionaires are currently funding our space successes and I hope this continues.
Thanks for reading.