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Date: Sat,  3 Mar 90 02:26:05 -0500 (EST)
Subject: SPACE Digest V11 #106

SPACE Digest                                     Volume 11 : Issue 106

Today's Topics:
		     Maximizing spacecraft speed
	       Discovery rollover date set (Forwarded)
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Date: Fri, 2 Mar 90 18:26:24 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Disclaimer: Opinions expressed are those of the sender
	and do not reflect NIST policy or agreement.
Subject: Maximizing spacecraft speed


>From: dino!sharkey!cfctech!joel@uunet.uu.net  (Joel Lessenberry)
>Subject: Experimentation

>        Along the same lines, has anyone considered the highest velocity
>        obtainable using current technology.  Again, the sole effort of
>        the project would be speed...so to speak.

I suspect the way to obtain the greatest speed for a "large" object using
near-term technology is to crash it into Jupiter or the sun. A recent posting
stated that the fastest man-made object thus far was Pioneer 11, which passed
within 26,600 miles of the cloud tops of Jupiter, moving at 107,373 miles
per hour. Of course, it lost a lot of this velocity as it moved away from
Jupiter.

The slingshot effect is used to add greatly to the speed of outer solar system
probes. According to Heinlein, another way to benefit from the gravitational
well of a planet or other body is to aim the craft in a free-falling hyperbolic
trajectory near the body. When you reach the lowest point in the gravity well
to be traversed, burn a large quantity of fuel in your rocket. Much of the
potential energy released by the fuel as it falls into the gravity well (inside
the rocket) is transferred to the craft.

I recently read of a proposal to use the sun for this purpose, to send a probe
out ~100 astronomical units, sometime early in the next century (Oct AWST?).
The probe would use a "reverse slingshot" around Jupiter to kill its solar
orbital velocity, then fall toward the sun, ultimately passing within a few
million miles (hot!). Near the sun, it would burn the remainder of its fuel.
In spite of their head start, it would pass the Voyager and Pioneer spacecraft
in a few more years, as though they were standing still.
                       John Roberts
                       roberts@cmr.ncsl.nist.gov

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Date: 1 Mar 90 22:52:06 GMT
From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov  (Peter E. Yee)
Subject: Discovery rollover date set (Forwarded)

[Somehow I think they meant roll out, not rollover. -PEY]

  Bruce Buckingham                                  March 1, 1990

  KSC RELEASE NO. 33 - 90


  NOTE TO EDITORS/NEWS DIRECTORS:

  DISCOVERY ROLLOVER DATE SET


       The orbiter Discovery, slated for Space Shuttle Mission STS-
  31, is scheduled to be transferred from the Orbiter Processing
  Facility Bay 2 to the Vehicle Assembly Building on Monday, March
  5, at 9:00 a.m.

       In the VAB, Discovery will be mated to the solid rocket
  boosters and external tank in high bay 1 on mobile launcher
  platform 2. Roll out to launch pad 39-B is set for March 16.

       Discovery is targeted for launch on April 12 on a mission to
  deploy the Hubble Space Telescope. The launch window on April 12
  opens at 9:21 a.m. EST and lasts for four hours.

       News media wishing to observe Discovery's rollover to the
  VAB should plan on being at the KSC Complex 39 news center by
  8:00 a.m., March 5. Media in need of accreditation can make
  arrangements by calling 407-867-2468 before the close of business
  Friday, March 2. (For media who have their STS-36 credentials,
  those credentials will be honored and no further arrangements are
  necessary.)

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End of SPACE Digest V11 #106
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