Stardust Spacecraft May Be Visible January 14-15
Date: Fri, 12 Jan 2001 17:31:45 -0800 (PST)
From: baalke@jpl.nasa.gov
Subject: Stardust Spacecraft May Be Visible January 14-15
Reply-To: stardust-owner@www.jpl.nasa.gov
To: undisclosed-recipients:;
Status: U
Stardust spacecraft may be visible Jan. 14-15
David Dunham (dunham@erols.com)
The Stardust spacecraft is returning to the Earth for a swingby
about two years after its launch, similar to NEAR’s Earth swingby
of 1998 Jan. 23. The best time to watch will be when the spacecraft
is at least 20 deg. above the horizon closest to the time of its
closest approach at about 11:15 U.T. January 15 U.T., and before
that closest approach, since it will be approaching the Earth with
a small phase angle (like NEAR) but departing with a much less
favorable approx. 90 deg. phase angle. For the Americas, the best
time will be around midnight Sunday night, Jan. 14-15. The best
areas for observation will probably be the Orient, and Australasia,
the western Pacific region. You can calculate an ephemeris for
your location using JPL’s ephemeris generator at
http://ssd.jpl.nasa.gov/horizons.html
Modify the “current settings” to select Stardust (in the “major body”
box) and select your city, or one near you, from their very extensive
city database (Greenbelt, MD, is in it). Then set the time interval
you want, and check the quantities you want in the ephemeris.
William Blume (JPL) gives some predictions of the observability ,
but based on the NEAR flyby experience, I think it will be a little
better, with Stardust probably being 11th mag. or brighter at the
best times in North America. The spacecraft attitude is being
controlled only in a “10 deg. deadband”, so there will be no solar
panel sunglint pointings like we did with NEAR. But you may be
lucky and see a brief direct reflection of sunlight from the solar
panels, which I think could be as bright as 4th to 6th mag.
David Dunham, IOTA
—————————————————————
From: “Jon Giorgini”
Subject: Stardust Trajectory
Latest Stardust post-maneuver, pre-Earth fly-by (Jan 15 11:15 UTC)
trajectory from the navigation team is accessible at:
telnet://ssd.jpl.nasa.gov:6775
(topocentric observer tables, elements, vectors. Type “stardust”,
then follow prompts. ? or ?! explains prompt.)
http://ssd.jpl.nasa.gov/horizons.html
(observer tables only)
— Jon Giorgini
J2000 Ecliptic heliocentric elements:
2451923.500000000 = A.D. 2001-Jan-14 00:00:00.0000 (TDB)
EC= 3.971868237175653E-01 QR= 9.562312821778280E-01
IN= 9.226679356159012E-03
OM= 2.715711750872453E+02 W = 2.293921980534217E+02
Tp= 2.451945915103786E+06
N = 4.933257195984641E-01 MA= 3.489420527949337E+02
TA=-2.732758968489939E+01
A = 1.586281321975960E+00 AD= 2.216331361774092E+00
PR= 7.297409920022358E+02
2451924.500000000 = A.D. 2001-Jan-15 00:00:00.0000 (TDB)
EC= 4.063483285001958E-01 QR= 9.556977718002366E-01
IN= 5.265180039460008E-03
OM= 2.514271634095720E+02 W = 2.495583077434385E+02
Tp= 2.451945852240112E+06
N = 4.825260407667660E-01 MA= 3.496969881171485E+02
TA=-2.617726537882492E+01
A = 1.609862850020715E+00 AD= 2.264027928241194E+00
PR= 7.460737236646049E+02
2451925.500000000 = A.D. 2001-Jan-16 00:00:00.0000 (TDB)
EC= 4.836314085399401E-01 QR= 9.831576808621124E-01
IN= 3.696307911459161E+00
OM= 1.153824850883206E+02 W = 3.571380138530885E+02
Tp= 2.451922649513395E+06
N = 3.751535291635117E-01 MA= 1.069370109702610E+00
TA= 3.508926751684556E+00
A = 1.903984280070525E+00 AD= 2.824810879278937E+00
PR= 9.596071261883104E+02
Symbol meaning [1 AU=149597870.691 km, 1 day=86400.0 s]:
JDTDB=Epoch Julian Date, Barycentric Dynamical Time
EC=Eccentricity,e
QR=Periapsis distance,q(AU)
IN=Inclination w.r.t xy-plane,i(degrees)
OM=Longitude of Ascending Node,OMEGA,(degrees)
W=Argument of Perifocus, w (degrees)
Tp=Time of periapsis (Julian day number)
N=Mean motion,n (degrees/day)
MA=Mean anomaly,M (degrees)
TA=True anomaly,nu (degrees)
A=Semi-major axis,a (AU)
AD=Apoapsis distance(AU)
PR=Orbital period (day)
