Page 5 of 6 FirstFirst ... 3456 LastLast
Results 41 to 50 of 51

Thread: Watch NASA’s Perseverance Rover Land on Mars!

  1. Top | #41
    Veteran Member
    Join Date
    Jun 2002
    Location
    West Coast
    Posts
    2,928
    Archived
    7,585
    Total Posts
    10,513
    Rep Power
    74
    Quote Originally Posted by skepticalbip View Post
    True, from the videos I've seen just lift-off from Earth would put the payload through a lot of stress... sorta like putting an instrument on the end of a stick and shaking it back and forth as hard as you can.
    I used to launch science experiments on suborbital rockets and you’d be amazed that coming back into the atmosphere put more stresses on it than launch.

    On the way up speed is increasing while pressure is decreasing. On the way down they’re both increasing. The ride up is at high g, indeed, but relatively smooth.

  2. Top | #42
    Veteran Member Treedbear's Avatar
    Join Date
    May 2016
    Location
    out on a limb
    Posts
    2,567
    Rep Power
    23
    Ingenuity has flown almost flawlessly through the red planet’s thin air and will now assist the science mission of the Perseverance rover.

    https://vp.nyt.com/video/2021/05/07/...eo_wg_720p.mp4

    “The plan forward is to fly Ingenuity in a manner that does not reduce the pace of Perseverance science operations,” said Bob Balaram, the chief engineer of the helicopter, in a NASA release after the flight.

    Ingenuity is expected to make just one or two more flights this month, taking off when there is time amid Perseverance’s other activities.

    But if that all goes well, Ingenuity could continue tagging along with Perseverance across the Martian landscape.

  3. Top | #43
    Administrator lpetrich's Avatar
    Join Date
    Jul 2000
    Location
    Eugene, OR
    Posts
    16,106
    Archived
    16,829
    Total Posts
    32,935
    Rep Power
    97
    I have been very neglectful of reporting of the flights of the Ingenuity helicopter.

    First Flight of the Ingenuity Mars Helicopter: Live from Mission Control - YouTube

    Videos | Multimedia Section – NASA’s Mars Exploration Program

  4. Top | #44
    Administrator lpetrich's Avatar
    Join Date
    Jul 2000
    Location
    Eugene, OR
    Posts
    16,106
    Archived
    16,829
    Total Posts
    32,935
    Rep Power
    97
    Ingenuity's blades spln at 2538 rpm or 42 Hz. But they are two counter-rotating ones, and they spin relative to each other at twice the frequency.

    Mars Helicopter - NASA Mars including Helicopter Status Updates - NASA Mars

    What We’re Learning About Ingenuity’s Flight Control and Aerodynamic Performance - NASA Mars

    The copter was tested in a giant vacuum chamber at JPL that is used for testing spacecraft. It was used to simulate the Martian atmosphere, with its density at the surface of about 1% the Earth's atmosphere. It is a rather soft vacuum by Earth standards.

    The surface pressure is about 6 to 7 millibars, comparable to that of the Earth's atmosphere at an altitude of 33.5 - 34.5 km (110 - 133 thousand feet). Sources: Aerospaceweb.org | Atmospheric Properties Calculator - 1976 Standard Atmosphere Calculator - calculators that use the 1976 Standard Atmosphere.

    Ingenuity's blades are controlled like those of full-sized helicopters, with their pitch (tilt angle) having "collective pitch" (the same over a rotation, for going up and down) and "cyclic pitch" (varying over a rotation, for going sideways).

    The copter uses a laser rangefinder and a camera to estimate altitude, using them only after reaching 1 meter altitude. Before that, it uses an "inertial measurement unit" (IMU) or accelerometer to estimate where it is. This is "dead reckoning", navigation by extrapolation and velocity and acceleration estimates, without direct updates of one's position.

    For Ingenuity's first flight, Mars's atmosphere density at the copter is 0.0165 kilograms per cubic meter, or about 1.3% the Earth's sea-level atmospheric density.

  5. Top | #45
    Administrator lpetrich's Avatar
    Join Date
    Jul 2000
    Location
    Eugene, OR
    Posts
    16,106
    Archived
    16,829
    Total Posts
    32,935
    Rep Power
    97
    Ingenuity (helicopter) - the remote-controlled helicopter carried to Mars by Perseverance (rover) nicknamed Percy

    On April 20, the MOXIE experiment produced some 5 grams of O2, enough to supply a typical astronaut for 10 minutes.

    That experiment used solid-state electrolysis, doing

    CO2 -> CO + (1/2)*O2

    But that has a problem: separation of carbon monoxide and oxygen. Their boiling points are very close, meaning that it may be hard to separate them.
    • CO: −191.5 °C, 81.6 K, −312.7 °F
    • O2: −182.962 °C, 90.188 K, ​−297.332 °F

  6. Top | #46
    Administrator lpetrich's Avatar
    Join Date
    Jul 2000
    Location
    Eugene, OR
    Posts
    16,106
    Archived
    16,829
    Total Posts
    32,935
    Rep Power
    97
    List of missions to Mars
    Here are the ones in operation:
    1. Mars Odyssey - NASA - orbiter - L 2001 Apr 7, A 2001 Oct 24 - (2025)
    2. Mars Express - ESA - orbiter - L 2003 Jun 2, A 2003 Dec 25 - (2026)
    3. Mars Reconnaissance Orbiter - NASA - orbiter - L 2005 Aug 12, A 2006 Mar 10
    4. Curiosity - NASA - rover - L 2011 Nov 25, A 2012 Aug 6
    5. Mangalyaan - ISRO (India) - orbiter - L 2013 Nov 5, A 2014 Sep 24
    6. MAVEN - NASA - orbiter - L 2013 Nov 18, A 2014 Sep 22
    7. ExoMars Trace Gas Orbiter - ESA - orbiter - L 2016 Mar 14, A 2016 Oct 19
    8. InSight - NASA - lander - L 2018 May 5, A 2018 Nov 26
    9. Hope - UAESA (United Arab Emirates) - orbiter L 2020 Jul 19, A 2021 Feb 9
    10. Tianwen-1 - CNSA (China) - orbiter, lander, rover - L 2020 Jun 23, A 2021 Feb 10
    11. Perseverance - NASA - rover, aircraft - L 2020 Jun 30, A 2021 Feb 18

    L = launch date, A = arrival date
    • Orbiters: 8
    • Landers: 1 (+1)
    • Rovers: 2 (+1)
    • Aircraft: 1

    The (+1) is for the Tianwen-1 lander and rover, which may arrive on the planet this month or the next.

  7. Top | #47
    Administrator lpetrich's Avatar
    Join Date
    Jul 2000
    Location
    Eugene, OR
    Posts
    16,106
    Archived
    16,829
    Total Posts
    32,935
    Rep Power
    97
    Ingenuity (helicopter)

    The copter has made seven flights so far:
    1. April 19
    2. April 22
    3. April 25
    4. April 30
    5. May 7
    6. May 23
    7. June 8
    8. (expected every 2 or 3 weeks until the end of August)


    The sixth flight was the first flight to land in a different place from its starting site. Surviving an In-Flight Anomaly: What Happened on Ingenuity’s Sixth Flight - NASA Mars
    Telemetry from Flight Six shows that the first 150-meter leg of the flight went off without a hitch. But toward the end of that leg, something happened: Ingenuity began adjusting its velocity and tilting back and forth in an oscillating pattern. This behavior persisted throughout the rest of the flight. Prior to landing safely, onboard sensors indicated the rotorcraft encountered roll and pitch excursions of more than 20 degrees, large control inputs, and spikes in power consumption.
    What happened?
    Approximately 54 seconds into the flight, a glitch occurred in the pipeline of images being delivered by the navigation camera. This glitch caused a single image to be lost, but more importantly, it resulted in all later navigation images being delivered with inaccurate timestamps. From this point on, each time the navigation algorithm performed a correction based on a navigation image, it was operating on the basis of incorrect information about when the image was taken. The resulting inconsistencies significantly degraded the information used to fly the helicopter, leading to estimates being constantly “corrected” to account for phantom errors. Large oscillations ensued.
    But it nevertheless survived.
    Despite encountering this anomaly, Ingenuity was able to maintain flight and land safely on the surface within approximately 16 feet (5 meters) of the intended landing location. One reason it was able to do so is the considerable effort that has gone into ensuring that the helicopter’s flight control system has ample “stability margin”: We designed Ingenuity to tolerate significant errors without becoming unstable, including errors in timing. This built-in margin was not fully needed in Ingenuity’s previous flights, because the vehicle’s behavior was in-family with our expectations, but this margin came to the rescue in Flight Six.
    Such overdesigning is a common engineering practice: Factor of safety

  8. Top | #48
    Contributor
    Join Date
    Nov 2017
    Location
    seattle
    Posts
    7,347
    Rep Power
    23
    In reliability there is a tradeoff between environmental screening and inducing long term failures in the secreting.

    'Shake and bake' vibration and temperature cycling.

    There are probably instruments on the probe that would not stand up to extreme vibration testing.

    Don't forget the Hubble mirror fiasco. Bad batteries were put on the ISS. Problems happen all the time. We only hear about the more visible ones.

  9. Top | #49
    Veteran Member Treedbear's Avatar
    Join Date
    May 2016
    Location
    out on a limb
    Posts
    2,567
    Rep Power
    23
    Quote Originally Posted by steve_bank View Post
    In reliability there is a tradeoff between environmental screening and inducing long term failures in the secreting.

    'Shake and bake' vibration and temperature cycling.

    There are probably instruments on the probe that would not stand up to extreme vibration testing.

    Don't forget the Hubble mirror fiasco. ...
    Slowly I turned. Step by step.

  10. Top | #50
    Contributor
    Join Date
    Nov 2017
    Location
    seattle
    Posts
    7,347
    Rep Power
    23
    Quote Originally Posted by Treedbear View Post
    Quote Originally Posted by steve_bank View Post
    In reliability there is a tradeoff between environmental screening and inducing long term failures in the secreting.

    'Shake and bake' vibration and temperature cycling.

    There are probably instruments on the probe that would not stand up to extreme vibration testing.

    Don't forget the Hubble mirror fiasco. ...
    Slowly I turned. Step by step.
    The best laid plans of mice and men....

    There used to ba site that listed all the probes and which ones failed and succeeded.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •