The photo above was taken by ESA of the Asteroid EROS... In the upper right corner you can see a strange object. This is one of the beat anomalies we have on file.

NEAR image of the day for 2000 May 3

This image of Eros, taken from the NEAR Shoemaker spacecraft on May 1, 2000, is among the first to be returned from "low orbit." Between May and August, the spacecraft will orbit at altitudes near 50 kilometers (31 miles) or less. This will be the prime period of activity for some of the spacecraft's science instruments. The X-ray / gamma-ray spectrometer will build up maps of chemical abundances, while the laser rangefinder measures the shape of Eros to within meters (a few feet). At the same time the magnetometer will watch for indications of Eros' magnetic field and the near-infrared spectrometer will map rock types.

The imager will take pictures of the entire surface of Eros that capture features as small as 4 meters (13 feet) across. This particular image, taken from an orbital altitude of 53 kilometers (33 miles), shows a scene about 1.8 kilometers (1.1 miles) across. Numerous craters and boulders as small as 8 meters (26 feet) across dot the landscape. The large, rectangular boulder at the upper right is 45 meters (148 feet) across.

(Image 0132577092) 

SOURCE: Near Earth Asteroid Rendevous (NEAR) JHU/APL

Here's an assessment of the feasibility of diverting asteroid 1981 Midas into a collision with Earth in the year 2018. I'm posting this to show the potential military-political advantage to controlling access to space.

Note the relatively small size of the divert delta-vee. Only about 301.5 meters per second will cause the asteroid to shift into a collision course.

Elements used for Earth.
a = 1.0000001124 AU
e = 0.0167102192
i = 0
L = 0
w = 103.078101 degrees
T = JD 2454468.667 (4:00:29 UT, 3 January 2008)

Elements used for 1981 Midas.
a = 1.7761208686 AU
e = 0.6501608192
i = 39.835472411 degrees
L = 357.03080224 degrees
w = 267.74138625 degrees
T = 2453926.666 (3:59:02 UT, 10 July 2006)

Midas divert delta-vee.
dV = 301.4552 m/s
RA = 17h 19m 45.192s
dec= -48.6042 degrees
Td = JD 2457809.620 (2:52:48 UT, 25 February 2017)

Transfer orbit is an ellipse with aphelion at departure.

Elements of the Midas transfer orbit.
a = 1.776419 AU
e = 0.6495124
i = 39.82184 degrees
L = 356.6238 degrees
w = 267.1621 degrees
T = JD 2457377.22 (17:16:48 UT, 20 December 2015)

Minimum distance between Earth's orbit and the Midas transfer orbit: 97.8 km
Minimum distance occurs at heliocentric longitude: 176.623768 degrees

Transit time = 384.379 days.
Impact on Earth at JD 2458194.0 (12h UT, 16 March 2018)

Midas approaches Earth from approximately
RA = 14h 2m
dec= +35.1 degrees
Facing Midas on arrival is: The North Pacific Ocean.
A vertical impact could occur: NE of Hawaii, S of Valdez AK, W of Los Angeles CA.

Midas' diameter: 3.4 kilometers
Assumed density: 2200 kg/m^3
Estimated mass: 4.5E+13 kilograms
Arrival speed in transfer orbit: 28.304 km/sec
Impact speed: 30.432 km/sec
Impact energy: 2.1E+22 Joules = 5.0 teratons TNT equivalent.

Jerry Abbott

RAND Corporation
Monograph reports MR1209 PDF
LOGISTICS

Availability

Two well known groups of asteroids—the Atens and the Apollos currently cross earth’s orbit, and each originates in the main asteroid belt between Jupiter and Mars. Astronomers have discovered 190 that are over 1 km in diameter and estimate that there are 900. In addition, the 1,500 Amor asteroids are believed to be very large nearearth objects that could pose significant future danger, having the
potential for global destruction.

Among the smaller, potentially useful objects may be over 1 million asteroids over 30 m in diameter that cross the earth’s orbit (Rabinowitz et al., 1994; Shoemaker et al., 1995). The objects among them that are important for this discussion have diameters ranging from a few tens of meters to a few hundred meters, depending on
whether they are stone or iron and on the effect desired. The relevant questions here are

• Can we reasonably expect to find enough of them?
• Do they pass near enough to the earth to be deflected enough for accurate collisions with the earth?
• Can this be done quickly enough?
• Can we expect to find them whenever necessary?

Diverting the course of an asteroid requires only a small DeltaV, if the deflection is done far enough in advance of earth impact. The displacement is proportional to both the lead time and DeltaV.1 Done well in advance, diverting an asteroid that would otherwise come no closer than midway between earth and moon requires imparting a DeltaV of at least several tens of meters per second to the asteroid. Deflecting an asteroid within days of its closest approach to earth would require a very large DeltaV, on the scale of kilometers per second. It is only possible to deflect an intermediate-size asteroid well in advance.