# Where to look for historical or reconstructed orbit data for early NASA missions - Mercury-Atlas 6 for example

After reading this answer to How many earth stations had astronauts on-site during John Glenn's orbit in Friendship-7? I decided that for my own use I'd like to plot the orbit of Mercury-Atlas 6, the spacecraft piloted by John Glenn on February 20, 1962. This thorough answer there lists fourteen (14) ground stations plus two additional radar tracking stations for telemetry and/or voice communication, spread out - roughly along the general path that the spacecraft wold follow.

Wikipedia's Mercury-Atlas 6 lists some parameters for an elliptical orbit in geocentric (inertial) coordinates. From these I should be able to find an ellipse whose ground track comes close to intersecting the launch and landing coordinates. There's some uncertainty there, but I'll see what happens tomorrow.

Perigee:       149 kilometers (80 nautical miles)
Apogee:        248 kilometers (134 nautical miles)
Inclination:   32.5 degrees
Launch site:   Cape Canaveral LC-14
Landing site:  21°20′N 68°40′W


While the TLE catalog available from space-track.org is convenient to use and indeed lists SatCat: 1962-003A, NORAD: 00240, it doesn't seem to have TLEs available. I requested data from the Celestrak "requestor" and have now received a second e-mail with the attached .txt file. No dice.

=====================================================================
00240 1962-003A   MERCURY ATLAS 6
Launched: 1962-02-20 (051)           Start Date: 1962-02-19 (050)
Decayed: 1962-02-20 (051)            Stop Date: 1962-02-21 (052)
=====================================================================
No data found for Catalog Number 00240
<End of file>


Question: Where to I look for historical or reconstructed orbit data for early NASA missions - Mercury-Atlas 6 for example.

Of course if there are more missions that would be great! I thought that I'd read years ago that NASA had put a collection of at least approximate, reconstructed trajectories somewhere for the public to access, but I can't find it now. I'm flexible on the form of the data, for example a table of state vectors, TLEs, or even one or more sets of Kepler orbital elements.

I suppose when I am done I can generate something like this display board shown below, but now I will also be able to plot approximate altitude, azimuth, and distance to each of the tracking stations as a function of time.

I'm not looking for such a plot, the answer I'm looking for will help suggest where I might find reconstructed orbit data.

above: View of Mercury Control at Cape Canaveral Air Force Station, in Florida (USA) during the Mercury-Atlas 6 mission, in February 1962. From here.

above: A ground-track map for Mercury-6 from here.

• Here is a better image: history.nasa.gov/SP-6/ch2.htm see Figure 2-1. But this is for the second orbital flight MA-7 with astronaut Carpenter. Another image here science.ksc.nasa.gov/history/mercury/ma-6/docs/ma-6-results.pdf page 6 of PDF, figure 1-1. This is for MA-6 with John Glenn. But I found no numerical orbit elements.
– Uwe
Dec 14, 2016 at 11:17
• Here is a lot of information about MA-6 ibiblio.org/mscorbit/document.html but I did not found orbital elements yet.
– Uwe
Dec 14, 2016 at 11:31
• The MA-6 Technical Report on ibiblio.org/mscorbit/document.html shows some trajectory parameters in Table II on page 26 to 28 of PDF A nice mixture of nautical and statue miles, velocities in foot per second. Good luck for the orbit plot.
– Uwe
Dec 14, 2016 at 11:46
• A map with good quality: hq.nasa.gov/office/pao/History/SP-45/fig8.1.htm
– Uwe
Dec 14, 2016 at 12:41
• Reference points on that map: CAL = Goldstone Lake, CA; GYM = Guaymas, Mexico; WHS = White Sands, NM; TEX = Corpus Christi, TX; EGL = Eglin AFB, FL; BDA = Coopers Island, Bermuda; ATS = Atlantic Tracking Ship; CYI = Gran Canaria, Canary Islands; KNO = Kano, Nigeria; ZZB = Zanzibar; CSQ = USNS Coastal Sentry; MUC = Muchea, Australia; WOM = Woomera, Australia; CTN = Canton (Kanton) Island, Kiribati; HAW = Kauai, Hawaii. Dec 15, 2016 at 7:10

For the record, @Uwe said this in a comment, which @uhoh considers an answer:

The MA-6 Technical Report on http://ibiblio.org/mscorbit/document.html shows some trajectory parameters in Table II on page 26 to 28 of PDF A nice mixture of nautical and statue miles, velocities in foot per second. Good luck for the orbit plot

That MA-6 Technical report says, for example:

TABLE II COMPARISON OF PLANNED AND ACTUAL TRAJECTORY PARAMETERS | Condition and Quantity | Planned | Actual | Difference | |----------------------------------------------------------------------| | Cutoff conditions (including tail- | | | | | off): | | | | | Range time, seconds | 303.3 | 302.0 | -1.3 | | min:sec | 05.03.3 | 05:02 | | | Geodetic latitude, | 30.4273 | 30.4533 | 0.0260 | | Longitude, deg west | 72.5268 | 72.5865 | 0.0597 | | Altitude, feet | 528,428 | 528,381 | -47 | | nautical miles | 57.00 | 56.96 | -0.04 | | Range, nautical miles | 436.4 | 433.7 | -2.7 | | Space-fixed velocity, feet per sec | 25715 | 26708 | -7.0 | | Space-fixed flight-path angle, deg | 0 | -.0468 | -.0468 | | Space-fixed heading angle, deg | | | | | east of north | 77.4756 | 77.4826 | 0.0070 | 

The original memo on calculating orbits like Glenn's (by Katherine Johnson, with Ted Skopinski, is The Determination of Azimuth Angle at Burnout for Placing a Satellite over a Selected Earth Position 1960. T.H. Skopinski, Katherine G. Johnson, NASA TN D-233.

As I note there, I'd also love to see recreations of the orbits, and especially comparisons of the orbits calculated according to the original methods (including the IBM 7090 approach), vs modern spacecraft kernel approaches.

For more on recreations of what those human computers, of Hidden Figures fame, did, see my answer at specific examples of the calculations human “computers” did for the Mercury space program?.

These data, showing state vectors for images (position, direction of view) from Apollo may also be of interest.

• This seems to be really interesting - I will take a day or two to look through it and try to take it all in - thank you very much! I'd asked an IBM 7090 ere question, but I hadn't seen your answer, thanks for calling my attention to it!
– uhoh
Apr 15, 2017 at 19:27
• @uhoh Thanks. I enjoyed that quest of yours on Frenet frame and the Gram–Schmidt process too! Apr 17, 2017 at 22:32
• – uhoh
Nov 24, 2019 at 15:22

This isn't super helpful, but too long for a comment: you might look the archived PDS SPK files at: http://naif.jpl.nasa.gov/naif/data_operational.html