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2161 Grissom (1963 UD)
Classification: Main-belt Asteroid          SPK-ID: 2002161
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbit Diagram
Note: Make sure you have Java enabled on your browser to see the applet. This applet is provided as a 3D orbit visualization tool. The applet was implemented using 2-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances. For accurate long-term ephemerides, please instead use our Horizons system.

Note: If the applet has stopped working because of a recent Java upgrade, here is a possible workaround.
Orbit Viewer

Additional Notes: the orbits shown in the applet are color coded. The planets are white lines, and the asteroid/comet is a blue line. The bright white line indicates the portion of the orbit that is above the ecliptic plane, and the darker portion is below the ecliptic plane. Likewise for the asteroid/comet orbit, the light blue indicates the portion above the ecliptic plane, and the dark blue the portion below the ecliptic plane.

Orbit Viewer applet originally written and kindly provided by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).

Orbital Elements at Epoch 2457600.5 (2016-Jul-31.0) TDB
Reference: JPL 20 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1621206965138701 5.6967e-08  
a 2.747344304434206 1.5607e-08 au
q 2.301942932235918 1.5625e-07 au
i 7.304580127534631 5.3182e-06 deg
node 126.4229637449178 4.5534e-05 deg
peri 249.6131301662774 4.7534e-05 deg
M 226.2176497991607 1.6028e-05 deg
tp 2458218.608024548956
7.6209e-05 JED
period 1663.290325693711
n .2164384620284821 1.8443e-09 deg/d
Q 3.192745676632494 1.8137e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1466  
   data-arc span      30862 days (84.50 yr)  
   first obs. used      1931-10-17  
   last obs. used      2016-04-15  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .49605  
   data source      ORB  
   producer      Otto Matic  
   solution date      2016-Apr-25 12:37:58  

Additional Information
 Earth MOID = 1.31381 au 
 Jupiter MOID = 2.2982 au 
 T_jup = 3.316 
[ show covariance matrix ]

Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 12.2 mag n/a MPO337264  
rotation period rot_per 5.0633 h n/a LCDB (Rev. 2016-February); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so.
Published Reference List:
[Vinson, R.; Moore, R.; Ditteon, R. (2014) Minor Planet Bul. 41, 169-170.]
[Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2016) Astron. J. 150, A75.]
SMASSII spectral type spec_B C   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)

2161 Grissom           Discovered 1963 Oct. 17 at the Goethe Link Observatory, Indiana University.
Named in memory of Virgil I. "Gus" Grissom (1926-1967), one of the seven Mercury astronauts. On 1961 July 21, as pilot of the Mercury-Redstone 4 suborbital mission, he became the second American in space. In 1965 he commanded a three-orbit mission, the first manned Gemini flight. As command pilot of Apollo 1, he lost his life in the tragic fire in that spacecraft. Name proposed by D. Owings and F. K. Edmondson. Citation prepared by Muriel M. Thorne, NASA.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: MPC 5848Last Updated: 2006-03-21

[ show close-approach data ]
Alternate Designations
 1963 UD = 1931 UN = 1976 OK 
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
FirstGov 2016-May-03 20:09 UT
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