Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modification of Roberts' Theory for Rocket Exhaust Plumes Eroding Lunar
  Soil   Roberts' model of lunar soil erosion beneath a landing rocket has been
updated in several ways to predict the effects of future lunar landings. The
model predicts, among other things, the number of divots that would result on
surrounding hardware due to the impact of high velocity particulates, the
amount and depth of surface material removed, the volume of ejected soil, its
velocity, and the distance the particles travel on the Moon. The results are
compared against measured results from the Apollo program and predictions are
made for mitigating the spray around a future lunar outpost.

23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an