• Thursday, February 21, 2019

Significant Challenges for SLS & Orion Programs

Discussion in 'World Affairs' started by Dante80, Feb 12, 2019.

  1. Dante80

    Dante80 FULL MEMBER

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    NASA Safety Panel: Significant Challenges Remain for SLS & Orion Programs

    February 11, 2019 - Doug Messier - ParabolicArc

    [​IMG]
    Space Launch System and Orion spacecraft on Pad 39B. (Credit: NASA)

    NASA’s plan to send astronauts back to the moon continues to make steady progress but faces significant challenges in manufacturing, flight control, software and other key areas as a crucial test of an abort system looms this spring, according to a new report released on Friday.

    A section of the NASA Aerospace Safety Advisory Panel’s (ASAP) Annual Report examined progress with the Space Launch System (SLS) rocket, Orion crew vehicle and Exploration Ground Systems (EGS) programs. An uncrewed flight of SLS and Orion known as Exploration Mission 1 (EM-1) is scheduled for next year.

    “[SLS] Core stage manufacture and qualification tests and the ESM [European Service Module] propulsion system continue to raise issues that affect both safety and schedule,” the report said. “In addition, flight control and ground system software has been a continuing concern and risk throughout the Program and remains an element on the critical path to EM-1 and later launches.

    “While progress is being made, software validation remains a considerable technical risk until completed,” the report added. “Software validation and verification is required before declaring the software operational, and it is not uncommon during this process to discover issues that need correction.”

    [​IMG]
    Orion spacecraft (Credit: NASA)

    ASAP is also concerned about Orion’s heat shield, which was significantly altered after an Orion spacecraft was launched on a flight test in December 2014. The new heat shield consists of blocks of heat-resistant materials with filler in between them. The report said the heat shield could fail if the blocks and gap filler ablate away at different rates during reentry.

    The panel is concerned that NASA could launch the EM-1 flight test even if avionics box designed to collect data about the heat shield’s performance isn’t functioning properly. ASAP said such a move would compromise a key objective of the mission.

    NASA’s alternative actions, which include recording the heat shield during reentry and examining it after Orion is recovered, might not be sufficient to validate the new design, ASAP said.

    “This approach is driven by the desire to avoid a launch delay in order to roll back the system to the Vehicle Assembling Building for avionics box replacement,” the report stated. “While we understand the reticence to accept such a delay, neither option guarantees enough information will be gathered to provide the needed understanding of heat shield performance.”

    ASAP also expressed reservations about a number of elements with the European Service Module (ESM) that will provide power and life support for the Orion capsule.

    [​IMG]
    The European Service Module for NASA’s Orion spacecraft is loaded on an Antonov airplane in Bremen, Germany, on Nov. 5, 2018, for transport to NASA’s Kennedy Space Center in Florida. For the first time, NASA will use a European-built system as a critical element to power an American spacecraft, extending the international cooperation of the International Space Station into deep space. (Credits: NASA/Rad Sinyak)

    “We remain very concerned and have reservations about the ESM propulsion system’s serial propellant system design, along with several of the zero-fault-tolerant design aspects of this system,” the report stated. “We understand the rationale and constraints that drove the decision for a serial system in the initial stages of the Program.

    “Several additional failures related to valve performance and integrated system behavior, in addition to the existence of the single-point failures, have only served to underscore the inadvisability of relying on a single-feed system for crewed missions to deep space for the longer term,” the document added.

    NASA is planning to shift from a serial to a parallel design for the propulsion system after the third SLS/Orion mission. However, ASAP said it was concerned the space agency is reconsidering that decision.

    The panel is also worried about whether Orion’s environmental control and life support systems (ECLSS) will be fully tested in time for Exploration Mission 2 (EM-2), which would be the first crewed mission.

    “Although NASA has informed the Panel about ECLSS testing, which is currently scheduled in 2021, we have not seen the plan for validation of the entire integrated system,” ASAP said. “While some components of the system are being operated on the ISS for microgravity experience, this component work does not substitute for integrated system operational validation.”

    ASAP said that SLS, Orion and EGS programs each has a risk management process that elevates the highest risks to NASA Headquarters for review. However, the panel questioned whether the risks are being sufficiently integrated across the three programs.

    “We do not yet know enough about how these elevated risks are integrated across all three programs in order to analyze their interdependencies,” the report stated. “Risk integration—and the evaluation of those integrated risks—is a critical portion of risk management.”

    As NASA deals with these technical issues, the space agency is preparing for a crucial test of Orion’s abort system, which would blast the capsule away from the SLS in the event of a booster failure. An Orion capsule with an abort motor will be launched on a small booster from Cape Canaveral this spring.

    “The ASAP strongly supports this test and the decision to gather the data as early as possible,” the report said.

    The relevant section of ASAP’s annual report follows.

    Source: http://www.parabolicarc.com/2019/02...ificant-challenges-remain-sls-orion-programs/
     
  2. Dante80

    Dante80 FULL MEMBER

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    Sadly, the program is still going one step forward and two steps back, in every milestone.
    And the main problem is still not addressed. There are no significant payloads for this LV, especially payloads designed for its specific mission.

    Those are going to cost as much as it will, or even more.
     
  3. Hamartia Antidote

    Hamartia Antidote ELITE MEMBER

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    I'm sure everybody would rather see that money go to the BFR.
     
  4. Dante80

    Dante80 FULL MEMBER

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    Well pretty much everybody...except the US Senate..SLS is dubbed the "Senate Launch System" for a reason..XD