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  [Discuss] NASA's Artemis-1 mission (Orion) (Page 4)

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Author Topic:   [Discuss] NASA's Artemis-1 mission (Orion)
Robert Pearlman
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posted 05-05-2022 10:18 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA plans to conduct another attempt of the wet dress rehearsal in early June to demonstrate the ability to load propellant into the tanks and conduct a full launch countdown ahead of the Artemis I launch this summer.

Robert Pearlman
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posted 05-16-2022 03:01 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
Artemis I Mission Availability

When Artemis I is ready to launch, a range of personnel from NASA, industry, and several international partners will be poised to support the mission. Before they get to launch day, the alignment of the Earth and Moon will determine when the Space Launch System (SLS) rocket with the uncrewed Orion spacecraft atop it can launch, along with several criteria for rocket and spacecraft performance.

To determine potential launch dates, engineers identified key constraints required to accomplish the mission and keep the spacecraft safe. The resulting launch periods are the days or weeks where the spacecraft and rocket can meet mission objectives. These launch periods account for the complex orbital mechanics involved in launching on a precise trajectory toward the Moon while the Earth is rotating on its axis and the Moon is orbiting Earth each month in its lunar cycle. This results in a pattern of approximately two weeks of launch opportunities, followed by two weeks without launch opportunities.

There are four primary parameters that dictate launch availability within these periods. These key constraints are unique to the Artemis I mission and future launch availability beyond this flight will be determined based on capabilities and trajectories unique to each mission.

  • The launch day must account for the Moon's position in its lunar cycle so that the SLS rocket's upper stage can time the trans-lunar injection burn with enough performance to successfully intercept the "on ramp" for the lunar distant retrograde orbit. The more powerful Exploration Upper Stage on future configurations of the rocket will enable daily, or near-daily, launch opportunities to the Moon, depending on the orbit desired.

  • The resulting trajectory for a given day must ensure Orion is not in darkness for more than 90 minutes at a time so that the solar array wings can receive and convert sunlight to electricity and the spacecraft can maintain an optimal temperature range. Mission planners eliminate potential launch dates that would send Orion into extended eclipses during the flight. This constraint requires knowledge of the Earth, Moon, and Sun along the planned mission trajectory path before the mission ever occurs, as well as an understanding of the Orion spacecraft's battery state of charge before entering an eclipse.

  • The launch date must support a trajectory that allows for the skip entry technique planned during Orion's return to Earth. A skip entry is a maneuver in which the spacecraft dips into the upper part of Earth's atmosphere and use that atmosphere, along with the lift of the capsule, to simultaneously slow down and skip back out of the atmosphere, then reenter for final descent and splashdown. The technique allows engineers to pinpoint Orion's splashdown location and on future missions will help lower the aerodynamic breaking loads astronauts inside the spacecraft will experience, and maintain the spacecraft's structural loads within design limits.

  • The launch date must support daylight conditions for Orion's splashdown to initially assist recovery personnel when they locate, secure, and retrieve the spacecraft from the Pacific Ocean.
The periods below show launch availability through the end of 2022. Mission planners refine the periods based on updated analysis approximately two months before they begin and are subject to change.

July 26 – August 10

  • 13 launch opportunities
  • No launch availability on August 1, 2, and 6
August 23 – September 6 (preliminary)
  • 12 launch opportunities
  • No launch availability on August 30, 31, and Sept. 1
September 20 – October 4 (preliminary)
  • 14 launch opportunities
  • No launch availability on Sept. 29
October 17 – October 31 (preliminary)
  • 11 launch opportunities
  • No launch availability on October 24, 25, 26, and 28
November 12 – November 27 (preliminary)
  • 12 launch opportunities
  • No launch availability on November 20, 21, and 26
December 9 – December 23 (preliminary)
  • 11 launch opportunities
  • No launch availability on December 10, 14, 18, and 23
The calendar also designates whether a launch on a particular date will beshorter in duration, of between 26 and 28 days, or longer in duration, of between 38 and 42 days. The mission duration is varied by performing either a half lap or one and a half laps around the Moon in the distant retrograde orbit before returning to Earth and increases the number of days the mission can launch and meet the above constraints

In addition to the launch opportunities based on orbital mechanics and performance requirements, there also is an operational constraint driven by infrastructure at NASA's Kennedy Space Center in Florida. Because of their size, the sphere-shaped tanks used to store cryogenic propellant at the launch pad can only supply a limited number of launch attempts depending on the type of propellant. Liquid oxygen and liquid hydrogen are loaded in the rocket's core state and upper stage on the day of launch. Should the launch subsequently be called off, there is a minimum of 48 hours until a second launch attempt can be made. There is then a 72-hour minimum before a third attempt can be made, due to the need to resupply the cryogenic storage sphere with more propellant from nearby sources. In any given week, no more than three launch attempts that include core stage tanking can occur.

Robert Pearlman
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posted 05-27-2022 11:56 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA has scheduled June 6 (beginning at midnight EDT) for the rollout of the Space Launch System (SLS) back out to Pad 39B.

The next wet dress rehearsal is targeted for no earlier than June 19, pending weather conditions.

Space Cadet Carl
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posted 06-07-2022 08:28 AM     Click Here to See the Profile for Space Cadet Carl   Click Here to Email Space Cadet Carl     Edit/Delete Message   Reply w/Quote
Is an onboard television system installed on Artemis-1 in order to provide live TV transmissions from the Moon?

Robert Pearlman
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posted 06-07-2022 09:32 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
According to NASA, there will be both live views inside and outside of Orion as it passes the moon, as well as video being recorded in high resolution and in possible other formats like 3D 360 degree VR.

Blackarrow
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posted 06-07-2022 01:09 PM     Click Here to See the Profile for Blackarrow     Edit/Delete Message   Reply w/Quote
I am reminded of the advice on making chicken soup attributed to the 19th century English cook, Mrs Beeton: "First catch your chicken."

Space Cadet Carl
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posted 06-08-2022 08:18 AM     Click Here to See the Profile for Space Cadet Carl   Click Here to Email Space Cadet Carl     Edit/Delete Message   Reply w/Quote
Correct. I'm also remembering how NASA initially argued that Apollo flights, specifically the Apollo 11 moonwalk really had little reason to be televised because it offered scant engineering return.

Headshot
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posted 06-09-2022 06:48 PM     Click Here to See the Profile for Headshot   Click Here to Email Headshot     Edit/Delete Message   Reply w/Quote
Will the NASA news coverage and television feed of this new wet dress rehearsal be the same as the previous one?

Robert Pearlman
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posted 06-09-2022 07:38 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA has yet to announce its coverage plans for the next wet dress rehearsal. When it does, the details will be posted here.

Headshot
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posted 06-09-2022 07:46 PM     Click Here to See the Profile for Headshot   Click Here to Email Headshot     Edit/Delete Message   Reply w/Quote
I hope that it will be better than last time.

Robert Pearlman
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posted 06-10-2022 05:18 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA is targeting Saturday, June 18, for the beginning of the next wet dress rehearsal with tanking operations on Monday, June 20.
NASA will provide live coverage of the test [with commentary] on NASA Television media channel, as well as host media calls before and after the wet dress rehearsal test with audio streaming live on the agency's website.
The rehearsal will begin at 5 p.m. EDT Saturday with the "call to stations." On Monday, the launch director and mission management team chair will decide at approximately 7 a.m. EDT if they are "go" to begin tanking. The team will count down to a targeted two-hour test window that opens at 2:40 p.m. EDT.

Robert Pearlman
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posted 06-20-2022 08:52 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
A summary timeline for the wet dress rehearsal can be found here. T-0 is now expected at 4:38 p.m. EDT.

Headshot
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posted 06-20-2022 11:19 AM     Click Here to See the Profile for Headshot   Click Here to Email Headshot     Edit/Delete Message   Reply w/Quote
In the camera 813 view, I see a liquid dripping/running off the main engine compartment of the core stage. It is just left of the center line and to the right of the left greenish rectangle. I would hope it is just water condensation and not liquid hydrogen or oxygen.

Robert Pearlman
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posted 06-20-2022 01:10 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
What you are seeing is likely condensation.

There is a reported liquid hydrogen leak from the quick disconnect that takes the bleed for the engines, but that is on the opposite side of the rocket from the view cited. Teams are currently evaluating the situation.

Robert Pearlman
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posted 06-20-2022 06:25 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
The hydrogen leak continues, but the mission management team and launch teams have completed their polls and are moving forward with a T-10 minute countdown in a modified configuration for the Artemis I wet dress rehearsal.

The hydrogen valve on the core stage has been closed as part of the steps being taken to mask the leak from the computers controlling the terminal count.

New planned T-0 is 7:37 p.m. EDT (2337 GMT).

From Jim Free, NASA's Associate Administrator for Exploration Systems:

We want to get most out of test today, because the more we do, the more we learn. We will get as deep as we can in the count, but may stop to keep SLS and Orion safe.

Robert Pearlman
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From: Houston, TX
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posted 06-20-2022 06:38 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
Hold at T-29 seconds. Vehicle safing has begun.

The reason for the countdown halting at T-29 seconds is not yet known. The plan had been to continue until T-9 seconds.

Robert Pearlman
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posted 06-20-2022 07:05 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
From launch director Charlie Blackwell-Thompson:
Like any tests we run, we'll go take the data, we'll go look at what we got, we'll go look at the couple of things that we didn't get and we'll lay out a plan for how we go forward. Probably a little premature to answer tonight after a long day, but certainly tomorrow we'll be back at it and we'll be looking at the data and laying out how we proceed forward.

Robert Pearlman
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posted 06-23-2022 12:30 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA has reviewed the data from the wet dress rehearsal and determined the testing campaign is complete. The agency will roll SLS and Orion back to the Vehicle Assembly Building (VAB) at Kennedy Space Center next week to prepare the rocket and spacecraft for launch and repair the hydrogen leak detected during the practice countdown.

NASA plans to return SLS and Orion to the pad for launch in late August. A specific target launch date will be decided after the work to fix the leak is completed.

Robert Pearlman
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posted 06-24-2022 11:09 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA is planning to roll back the Space Launch System to the Vehicle Assembly Building on July 1. There, the rocket will spend five to eight weeks undergoing inspections and a repair to correct for the hydrogen leak.

As of today, a launch attempt in late August is still possible. The first two available windows are Aug. 23 through Sept. 6 and Sept. 19 through Oct. 4. NASA expects to announce the launch date in a few weeks.

Robert Pearlman
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From: Houston, TX
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posted 07-02-2022 01:56 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
Rollback of the Artemis I Space Launch System and Orion spacecraft was completed between 4:12 a.m. and 2:30 p.m. EDT (0812 and 1830 GMT) on Saturday (July 2).


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