1) The use of a heat shield made from asteroidal materials is highly attractive because it reduces propulsion requirements.

2) The average frequency of Tunguska-like asteroidal collisions ranges from one in 200 years to one in 1,000 years.

3) The glass in the regolith owes its origin to impacts of cometary and asteroidal material with the lunar surface.

4) The only force generally believed to be sufficiently powerful is the high-energy impact of a large asteroidal fragment on the Moon.

5) The expansion of human civilization into space is feasible because of the availability of vast asteroidal and planetary resources.

6) The report of the review board concludes unequivocally that the accident was caused by a high-altitude aerial explosion of an asteroidal body.

7) Because at least one asteroid appears to be coated by a thin layer of ice. And just that kind of asteroidal frosting could have been the source of our water here on Earth.

8) The researchers concluded that the heat generated by the joint decay of 26Al and 60Fe could not have caused asteroidal melting.

9) In summary, a fair appraisal of the evidence indicates that collisions and the decay of 26Al were both important sources of asteroidal heating.